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i 


A 


COMPENDIUM 

OF  THE 

ANATOMY 

OF  TKE 

HUMAN  BODY. 

INTENDED  PRINCIPALLY  FOR  THE  USE  OF  STUDENTS; 

BY  ANDREW  FYFE. 

IN  TWO  VOLUMES. 


VOL.  II. 


This  Edition  is  prefixed  with 

A Compendious  History  of  Anatomy, 

And  tbs 

Ruvschian  Art  and  Method 

Of  making  Preparations  to  exhibit  the  Structure  of  the 
Human  Body,  illufiratcd  with  a Reprefentation  of  the 

Quicksilver  Tray  and  its  Appendages, 

Which  are  not  in  the  London  Edition. 


PRINTED  AND  SOLD  BY  JAMES  HUMPHREYS, 

Ac  che  N.W.  Corner  of  Walnut  and  Dock-ftreets. 


COMPENDIUM 


OF  THE 

ANATOMY 


HUMAN  BODY, 

INTENDED  PRINCIPALLY  FOR.  THE  USE 
OF  STUDENTS. 

By  ANDREW  FYFE. 

IN  TWO  VOLUMES. 

VOL.  II. 

'RENTED  AND  SOLD  BY  JAMES  HUMPHREYS, 
At  the  N.  W.  Corner  of  Walnut  and  Dock-ftreets. 


PART  IV. 


OF  THE 


VISCERA, 

AND 

ORGANS  OF  THE  SENSES. 


OF  THE  -COMMON  INTEGUMENTS. 

The  Cuticle. 

^ir^KF,  Cut  id’.  Epidermis,  or  Skarf-Skir. , is  a thin  femitranf- 
X parent  infenlible  Membrane,  which  covers  the  Skin,  and 
adheres  to  it  by  fmall  Vafcular  Filaments. 

The  Cuticle  is  readily  [epa.ra.ted  from  the  Cutis  by  boiling 
water,  or  by  putrefaction,  and  in  the  living  body,  by  the  appli- 
cation of  blitters. 

It  is  not  every  where  of  the  fame  denfity,  being  even  in  the 
Foetus,  thickelt  in  the  Palms  and  ' Soles ; in  which  parts,  the 
thicknefs  is  afterwards  much  increafed  by  pr.efiure. 

The  External  Surjace  is  marked  by  Furro-ivs,  which  corref- 
pond  with  tliofe  in  the  Cutis  Vera. 

Upon  the  Surface  of  the  Body  it  is  perforated  by  the  termina- 
tion of  the  Exhalent  VetTels, — which  throw  out  the  Perfpirable 
Matter,  and  which,  when  increafed,  is  confidered  by  molt  of  the 
modern  Phyflologifts,  as  forming  the  Sweat; — by  the  ends  of 
the  Excretory  DuCts,  which  are  found  in  particular  parts  of  the 
Skin; — by  the  beginnings  of  the„Abforhents,  which  take  in 
certain  Subrtauces  applied  to  the  Surface  of  the  Skin  ; and — by 
the  different  flairs. 


4 


Tlie  Perforations,  or  Pores,  are  mofi  evident  upon  the  Palms 
and  Soles,  and  upon  the  Nol'e,  Ears,  and  external  parts  or  Ge- 
iteration. 

The  Cuticle  covers  the  Skin  through  its  whole  extent,  excep- 
ting under  the  Nails. 

From  the  External  Surface  of  the  Body,  it  is  reflected  in- 
wards,  to  line,  the  large  Paffages ; as  the  Alimentary  Canal,  the 
T rachea,  the  Urethra,  Vagina,  &c. 

In  thefe  Pafl'ages,  however,  the  Cuticle  becomes  lefs  uniform 
in  its  texture  ; and  in  feme  of  them,  as  in  the  Stomach,  is  either 
awanting,  or  is  lo  much  changed  in  ftrufture,  as  to  have  the  ap- 
pearance of  beinCT  f0. 

From  the  Surface  of  the  Cuticle,  certain  Proceffes  are  fent 
into  the  Skin,  which  line  the  Paffages  by  which  the  Cutis  is  per- 
Jorated. 

Many  opinions  have  been  advanced  concerning  the  origin  of 
the  Cuticle  : — the  Intel!  and  molt  probable  is,  that  it  is  iornted 
by  a condenfatien  of  the  Corpus  Mucofum,  or  by  the  Exticmi- 
lies  of  Excretory  Veffels; — its  denfity,  however,  is  fuel),  that 
no  veffels  can  be  traced  in  it,  either  by  the  Eye  or  by  the  affilt- 
ance  of  glaffes. 

The  Cuticle  ferves  to  preteft  the  fenfible  parts  under  it ; and 
to  regulate  the  proportion  of  the  Fluids  thrown  out  or  taken  in 
by  the  Surface  cf  the  Skin  ; — paiticularly  to  prevent  too  great  a 
dtgiee  of  evaporation. 

Corpus  Mucosum.  • 

The  Corpus  Mucofum  has  been  commonly  called  Rete  Mucofum, 
from  the  fuppofition  that  it  is  formed  of  a Mucous  Net  work,  and 
is  fituated  under  the  Cuticle  which  it  connects  to  the  Cutis 
Vera. 

It  is  compofcd  of  the  teiminations  of  extremely  minute  Veffels 
paffinr,  between  the  Cutis  and  Cuticle,  which  are  fui  rounded  by 
a Mucilaginous  or  Vifcid  Subfiance,  properly  called  Corpus  Mu- 
cofum. 

It  is  the  chief  caufe  of  that  variety  of  colour  which  chat'after- 
ifes  the  natives  of  d fferent  climates,  ar,d  different  people  of  the 
fame  climate,  being  white,  or  rather  of  a light-grey  femi  tiar.f- 
parent  colour  in  the  European,  black  in  the  Ethiopian,  brown  in 
the  Aliatic,  &c. 

It  is  thicker  and  frenger  in  the  Negro  than  in  the  white  pev- 
fon,  and  can  be  readily  separated  in  the  fcimer  into  two  Layers. 

It  covers  every  part  of  the  Surface  of  the  Cutis,  exceptmg 
below  the  Nails,  where  it  is  awanting  ; and  is  of  f'uch  a light 
colour  in  the  Palms  and  Soles  of  the  Negro,  as  to  have  been  fup- 
pofed  by  Ionic  authors  to  be  deficient  there  all’o. 


5 


Its  origin  has  not  yet  been  fufficiently  ascertained,  nor  is  it  fully 
determined  what  particular  purpofes  it  ferves.  . 

Among  other  purpofes,  however,  it  contributes  to  preferve 
the  Itruflure  of  the  tender  Vellels,  Duffs,  and  Papillae,  placed 
between  the  Cutis  and  Cuticle  ; and  in  the  Negro,  it  is  fup- 
pol’ed  to  ferve  as  a defence  againtl  the  heat  of  the  climate,  by 
preventing  the  rays  of  the  Sun  from  penetrating  the  Skin. 

Cutis  Vera. 

The  Cutis  Vera,  or  Skin,  propei  iy  fo  called,  lies  immediately 
under  the  Corpus  Mucofum,  and  gives  a general  covering  to  the 
whole  Body. 

It  is  formed  of  Fibres  intimately  interwoven,  and  running  in 
every  dueftion,  and  is  fo  plentifully  {'applied  w th  Nerves  and 
Blood- Veffels,  that  the  fmallelt  punfttire  cannot  be  ma.le  in  any 
part  of  it,  without  occafioning  pain  and  bringing  Blood. 

The  Blood-Veffels  of  the  Cutis  are  fo  numerous,  as  to  appear 
to  form  almolt  the  whole  of  its  Subitance,  and  are  of  fuch  a iize 
as  to  be  readily  injefted. 

It  is  ftrong  and  elalflc,  and  may  be  elongated  in  every  direc- 
tion, after  which  it  recovers  its  former  dlineniions. 

It  forms  the  body  of  the  Skin,  and  is  that  part  in  Quadrupeds 
of  which  Leather  is  made. 

The  outer  pa<t  of  it  is  denfe  and  firm,  the  inner  loofe,  and 
gradually  degenerating  into  the  common  Cellular  Subitance. 

It  is  thicker  and  loofer  on  the  polterior  than  on  the  anterior 
part  of  the  Body,  an-d  thicker  and  .firmer  in  the  Palms  and  Soles 
than  in  the  other  parts  or  the  extremities. 

The  colour  of  the  Cutis  alio  differs  in  different  parts  of  the 
body,  in  proportion  to  the  quantity  of  Blood  in  the  extreme  Vei- 
l'd?, and  to  the  thiunefs  of  the  Cuticle. 

At  the  edge  of  the  Eye-lids , the  red  part  of  the  I ips,  and  mar- 
gin of  the  Anus,  the  Cutis  becomes  i'o  immediately  and  remarka- 
bly thin,  as  to  appear  to  be  loll. 

Upon  the  Surface  of  the  Cutis,  fmall  Eminences  are  obferved, 
ca.led  Papilla:,  Papilla  Nervo fa,  and  Papilla  Pyramidales  j the 
term  being  borrowed  from  the  Papilla?  of  the  fonsue,  which 
were  firft  dilcoyered,  and  to  which  the  name  is  rnoft  applicable. 

They  are  ccnlkierecl  as  forming  the  Organ  of  Touch,  from 
their  being  extremely  fenfible  ; and  from  their  being  very  Vaf- 
cular,  tney  are  alio  regarded  as  furnilhlng  a paflage  to  part  of 
the  Perfp'rable  Matter. 

The  Papilla  are  rnofc  evident  in  the  Palms  and  Soles,  where 
they  are  placed  in  double  rows  upon  the  ridges,  which  on  the 
points  of  the  Fingers  and  Toes,  generally  run  in  a fomewhat 
Ipiral  and  parallel  direction. 

V Ob,  II,  A 2,  | 


6 


The  Ridges  ate  fuppofed  to  defend  the  Papillae,  and  to  increafe 
the  Suitace  for  Perlpiration. 

In  fome  places,  as  in  the  red  part  of  the  Lips,  the  Papillae  are 
termed  Villi,  from  their  refemblance  to  the  p.le  of  Velvet. 

Various  kinds  of  folds  are  obferved  in  the  Sk>n  ; fome  depend- 
ing upon  the  form  of  the  Cellular  Subftance,  as  in  the  Hips  j 
others  on  Mufcular  Contraction,  as  in  the  Fore-head  ; and 
others  on  Articular  Motion,  as  at  the  Joints  of  the  extremities, 
—particularly  thofe  of  the  Fingers  and  Toes;— and  thefe  folds 
are  thinner  than  the  reft  of  the  Skin,  to  allow  eafy  motion. 

In  an  inflamed  Skin,  as  in  the  cafe  of  Small-pox,  a Reticular 
Texture  of  Vefiels  is  obferved,  which  can  be  eafily  injefted,  and 
has  been  coniidered  by  fome  as  the  Corpus  Mucofum,  and  by 
others  as  an  additional  Cuticle ; — but  no  fitch  appearance  is  to  be 
met  with  in  the  found  Skin. 

ff  he  Cutis  Vera  ferves  to  cover  and  give  form  to  the  Body,  it 
unites  the  different  parts,  and  defends  them  from  injury.  It 
forms  (he  External  Organs  of  Senfatiun  or  of  Touch,  and  gives 
paffage  to  the  Fluids  which  are  Perfpired  or  Ablorbed. 

APPENDAGES  OF  THE  SKIN. 

Nails. 

The  Nails  were  formerly  regarded  as  a continuation  of  the 
Papillae  of  the  Cutis,  but  are  now  more  generally  confidered  as 
a continuation  of  the  Cuticle. 

They  are  removed  along  with  it  by  boiling  water,  or  by  ma- 
ceration. 

Like  the  Cuticle  alfo,  they  are  infenfible,  are  renewable  after 
having  been  feparated,  and  have  no  evident  Veflels. 

They  differ  from  it,  however,  in  ftrufture,  being  formed  of 
Plates,  and  thefe  of  Longitudinal  Fibres,  which  are  ciofely  com- 
pared. 

They  begin  by  a fquare  root,  a little  before  the  laft  Joint  of 
the  Fingers  and  Toes. 

When  feparated  from  the  Skin,  they  are  tranfparent  like 
Horn,  but  are  coloured  in  the  living  Body  by  the  Veffels  of  the 
Cutis,  to  which  they  adhere,  and  from  which  they  derive  their 

nonriftiment. 

They  are  fixed  at  their  roots  to  a femilunar  fold  of  the  Cutis, 
and  are  there  covered  by  a refle&ion  of  the  Cuticle,  which  firmly 
adheres  to  them. 

They  grow  from  the  roots,  and  not  from  the  points. 

The  nails  ftrengthen  and  defend  the  ends  of  the  Fingers  and 
Toes,  and  thereby  ferve  as  Buttreftes. 


7 


In  the  Fingers  they  increafe  the  power  of  apprehenlton,  being 
ufetul  in  laying  hold  of  minute  objects. 

Hairs. 

The  Hairs  arife  by  roots  or  bulbs,  which  are  iituated  in  the 
Cellular  Subftance  under  the  Skin. 

The  Bulbs  are  of  various  lhapes  in  different  parts  of  the  B jdy, 
and  have  Blood-Veffels  difperled  upon  them  for  their  nourifh- 
ment. 

Each  of  the  Bulbs  has  two  Membranes,  or  Capfules,  conta:n- 
ing  an  Oily  Fluid  between  them,  which  gives  colour  to  the  Hair, 
and  for  want  of  which,  as  in  advanced  life,  or  in  certain  difeales, 
the  Hair  is  fuppofed  to  change  its  colour,  and  become  white.  It 
may  be  remarked,  however,  that  the  Hair,  after  being  cut  off, 
continues  uniformly  to  prelerve  its  colour. 

The  body  of  the  Hair  coniifts  of  fraaller  hairs  inclofed  in  a 
Membrane,  and  is  fomewhat  of  the  nature  of  the  Nails.  Like 
them  alfo,  it  grows  only  from  the  root. 

The  ufe  of  the  Hair  is  not  yet  fully  known. — It  ferves  in  general 
for  the  ornament,  warmth,  or  protection  of  the  different  parts  on 
or  near  which  it  is  placed. 

Sebaceous  Ducts  or  Follicles,  and  Miliary 
Glands. 

The  Sebaceous  Follicles  derive  their  name  from  the  Fluid  they 
contain  becoming  like  Suet,  after  acquiring  a certain  degree  of 
confiftency,  or  being  inl'piffated  by  ftagnation. 

They  are  feated  under  the  Cutis,  and  are  found  in  greateft 
abundance  in  thole  parts  which  are  expofed  to  the  air,  or  to  at- 
trition ; as  in  the  Nofe,  Ears,  Nipples,  Groins,  and  external 
Parts  or  Generation. 

The  Sebaceous,  or  Miliary  Glands , are  fo  called  from  their 
contents,  and  from  their  refemblance  to  Millet  Seeds,  and  are 
feated  in  the  Axilla. 

Other  Mil. ary  Glands  are  deferibed  by  Authors  as  being 
placed  under  the  Skin  over  the  whole  Surface  ot  the  Body,  and 
as  ferving  for  the  fecretion  of  Perfpirable  Matter  but  they  are 
not  demonftrable  to  fuch  a general  extent ; and  the  Sweat  tscon- 
fidered  as  being  derived  from  another  fource. 

Thefe  Follicles  and  Glands  fecrete  a fluid  which  ferves  to  lu- 
bricate the  Skin,  and  defend  it  from  the  inclemency  of  the  weather, 
or  from  the  effects  of  fri&ion. 

Membrana  Cellularis,  or  Tela  Cellulosa,  or 
Reticular,  or  Cellular  Substance. 

This  is  generally  confidered  as  one  of  the  Integuments, 
though  common  to  thefe  and  to  the  other  parts  of  the  Body. 


8 


It  is  compofed  of  a fine  web,  formed  of  many  Membranes  join 
ed  irregularly  together,  and  thefe  made  up  of  Cells,  which  com- 
municate freely  with  each  other  wherever  they  are  found. 

It  is  very  elalfic,  may  be  drawn  out  to  a confiderable  extent, 
after  which  it  t'uddenly  recoils,  and  may  be  condenied  or  com- 
pared to  a great  degree. 

It  lines  the  Skin,  covers  the  Mufcles  in  general,  and  enters  in 
between  their  different  Fibres; — is  an  univerfal  covering  to  all 
the  other  parts,  and  even  enters  into  the  compofition  of  almoft 
every  one  of  them. 

It  is  thickelf  where  the  parts  are  moftexpofed  to  preffure,  as  in 
the  Hips,  Palrns,  and  Soles. 

The  different  Cells  of  which  it  is  compofod,  are  conftantly 
moinened  by  an  Intel ltitial  Fiuid,  and  in  many  parts  of  the 
Body  are  fi  led  with  Fat. 

It  has  little  cr  no  lenfibility,  can  be  handled  freely,  or  cut  or 
punftured  without  giving  pain. 

It  ferves  to  conneft  parts  to  each  other, — but  fo  as  to  prevent 
them  from  growing  together  ; — it  covers  them,  fupplies  them  with 
fhcaths  to  move  in,  and  contains  the  Fat. 

Corpus  Adiposum,  Adeps,  Pinguebo,  or  Fat. 

The  Fat  is  lodged  in  the  common  Cellular  Subftance,  but  with- 
cut  communicating  with  it,  and  s made  upot  Mafles  compcfed  of 
I'm  a 1 1 Vehicles  containing  the  Fat,  and  thefe  are  furrounded  by  a 
net  work  of  Blood- VcfTels,  £ om  which  the  Fat  is  fuppofed  to  be 
fecieterl,  with  ut  the  intervention  of  Glands. 

The  Ve.fules  are  not  found  to  have  any  communication  with 
each  other,  n»r  have  any  Excretory  Duffs  yet  been  perceived  in 
them, — he  Fat  being  fuppufed  to  tranfude  from  the  Cells. 

Ii  is  of  different  canfifeney  in  different  paits  i f the  Body  : In 
the  living  Eody  it  is  generally  fluid,  though  in  fome  parts  it  ap- 
proaches" to  a iulid,  and  is  altogether  of  "this  nature  in  the  dead 
Body. 

In  the  Bones  it  forms  the  Marrow,  which  has  been  formerly 
defer i bed . 

The  Fat  is  chiefly  fituated  immediately  under  the  Skin,  and 
covers  almoft  the  whole  Sm  face  of  the  Body.  It  is  aifo  found 
between  the  different  Mufcles  and  Fibres  of  Mufcles, — within 
the  Orbits,  anu  in  the  Cheeks, — in  the  Subftance  of  the  Main- 
ffiae,  and  about  the  Heart. 

\ It  abounds  ir.  the  Abdomen,  about  the  Kidneys,  Loins,  Omen- 
ti\m,  and  Mefentery; — and  in  the  Joints  it  forms  the  Subflan- 
ce^  called  Glands  of  the  Joints,  already  mentioned. 

The  Fat  is  awatiling  in  the  Scrotum,  Penis,  and  Eye-Lids, 
and  is  found  only  in  final  1 quantity  in  the  Fore-head,  or  about 
the  Joints,  where,  from  its  bulk,  it  would  have  been  jjpnconvuH- 


V 


eut. — It  is  alio  awanting  in  the  Subffance  of  the  Vifcera  fituated 
n the  great  Cavities  of  the  Body;  as  the  Brain,  Lungs,  Liver, 
Spleen,  Kidneys,  &c. 

The  Fat  ferves  to  lubricate  every  part  of  the  Body  to  which  it 
is  connefted,  and  facilitates  the  adlion  of  the  Muicles.  It  fills 
the  Interflices,  fo  as  to  give  form  and  fmoothnefs,  and  guard 
againtl  prefl’ure.  It  ferves  all’o  as  a refervoir  of  nourifhment. 

Panniculus  Car.nosus, 

Defcribed  by  the  Ancients  as  an 
Additional  Covering. 

This  is  a general  Covering  found  in  the  Quadruped,  and 
formed  by  a thin  Subcutaneous  Mufcle,  which  ferves  to  agitate 
the  Skin. 

It  is  found  only  in  certain  parts  of  the  Human  Body;  as  in 
the  Fore-head,  where  it  is  formed  by  the  Occipito, Frontalis 
Ivlufcle  ; and  in  the  Neck,  where  it  is  formed  by  the  Platyfnva 
Myoides, 


•OOOOOOOO®  OOOOOOOO' 


OF  THE  BRAIN . 


THE  term  Brain  is  applied  to  the  whole  of  that  Mafs  which, 
with  its  furrourtding  Membranes,  fills  the  Cavity  of  the  Crani- 
um ; and  is  larger  in  Man,  in  proportion  to  the  fize  of  the  body, 
titan  in  any  other  animal. 

The  Membranes  of  the  Brain  were  called  Meninges  and  Ma- 
ters by  the  Ancients,  from  an  idea  that  they  gave  birth  or  ori- 
gin to  all  the  other  Membranes  of  the  Body. 

They  co  nil  if  of  the  Dura  Mater , Tunica  Arachnoidea,  and  Pia 
Mater. 

The  Dura  Mater,  named  from  its  being  of  a firmer  tex- 
ture than  the  other  two  Membranes, . ir.clofes  the  Brain  and  all 
its  Appendages,  and  lines  the  different  parts  of  the  Cranium. 

It  is  compofcd  of  one  Membrane,  whk  h,  in  feveral  parts, 
is  diviiible  by  maceration  into  two,  or  even  more  layers  of  Fi- 
bres. 


10 


The  texture  of  the  Dura  Mater  is  very  denfe.  It  is  the 
thickeft  and  ftrongefl  Membrane  of  the  B -dy,  and  is  c ::  r fed 
of  Tendinous  like  Fibres,  winch  have  a Aiming  appearance, 
particularly  in  its  inner  Surface.  In  many  parts  !•->«  Fibre* 
run  in  a variety  of  dire&ions,  and  deculfate  eac,  ^ '.Affer- 
ent angles. 

The  Dura  Mater  adheres  every  where  to  the  Surface  of  ti  e 
Cranium,  in  the  fanie  manner  as  tin-  . ..  . S •.  ■ a c the 

Bones  in  the  other  parts  of  the  Body  it  : *rw« 
nefled  at  the  Sutures  and  Ftratnim’.  tit  an  .'-h'ewkere  ; an.-,  fo 
much  more  firmly  in  Children  tr 

it  from  the  Cranium,  it  is  apt  to  bring  along  with  it  fome  of  the 
Fibres  of  the  Bone  to  which  it  is  a1:' rube.!  ■ • -In  t!  e adult,  the  Se- 
paration of  the  Bone  from  the  Mem  Inane  is  •••is  dii  • :c 
fequence  of  many  of  the  Fibres  being  obhterau  d 

The  inner  Surface  of  the  Dura  Mater,  which  is  remarkably 


finooth,  is  in  clo'c  con  tail  with  te  Train,  but  adheres  only  where 
the  Veins  go  into  the  ’ i tufes,— ■ and  v lul  • ; to  by  a Fluid  dis- 
charged through  its  V<  iH-ls,  v,  h guards  the  Brain  from  dan- 
ger, according  as  it  may  be  abetted  by  the  different  flutes  of 
Refpiration. 

The  Dura  Mater  ferves  as  a defence  to  the  Brain,  and  fup- 
plies  the  place  of  a PerioJUum  to  the  infide  of  the  Bones  of  the 
Cranium,  giving  nourifhment  10  them,— -as  is  evident  from  the 
numerous  drops  of  JJlo.ud  which  appear  after  removing  the 
Skull-cap. 

From  the  inner  fide  of  the  Dura  Mater,  Procejfes  are  fen t off, 
which  divide  the  Brain  into  certain  parts,  and  lerve  to  keep  it 
Heady,  viz. 

I.  The  Falx,  Superior  Longitudinal  Procefs,  or  Septum  Cere- 
bri, which  is  formed  by  a doubling  of  the  Dura  Mater,  and  is 
fituated  between  the  Hemifpheres  of  the  Brain. 

It  begins  at  the  middle  of  the  Sphenoid,  and  Crifta  Gal  1 i of  the 
Ethmoid  Bone,  and  runs  along  the  upper  and  middle  part  of  the 
Head,  adhering  firfl  to  the  Frontal,  then  to  the  joining  of  the 
Parietal,  and  afterwards  to  the  middle  of  the  Occipital  Bone. 

In  its  paffage  it  becomes  gradually  broader,  cxiends  from  the 
Cranium  to  near  the  Corpus  Callufum,  and  terminates  behind  in 
the  middle  of  the  Tentorium. 

It  luns  from  behind  forwards  in  a Araight  direction,  and  has 
fome  refembh.nce  in  fliape  to  a Sickle  01  Scythe , from  which  cir- 
cumltance  it  has  obtained  the  name  of  Falx. 

Between  the  under  edge  of  the  Falx  and  Bafe  of  the  Cranium, 
there  is  a large  /pace,  of  an  oval  faun,  occupied  by  that  pait  of 
the  Brain  which  is  common  to  the  two  Hemifpheres. 

The  Falx  fupports  the  Tentorium,  and  prevents., the  two  tides 
of  the  Brain  from  prefling  upon  each  other.  , 


11 


II.  The  Tentorium  CEREBELLi,or  Tranjverfe  Septum,  ol 
Lateral  Procejfes  of  the  Dura  Mater. 

The  ’Tentorium  is  continued  laterally  from  the  Falx,  is  con- 
ne£ted  behind  to  the  inner  Tranfverfe  Ridges  and  Grooves  of 
the  Occipital  Bone,  and  at  the  fore  and  outer  edges,  to  the 
Ridges  and  great  Angles  of  the  Temporal  Bones,  and  terminates 
at  the  Pofterior  Ciinoid  Procefs  of  the  Sphenoid  Bone. 

Between  the  middle  and  inner  edges  of  the  Tentorium  and 
pofterior  Ciinoid  Procefs  of  the  Sphenoid  Bone,  there  is  a large 
Notch,  or  Foramen  Ovale,  where  the  Brain  and  Cerebellum  are 
united,  or  where  the  Tuber  Annulare  is  chiefly  fituated. 

The  Tentorium  keeps  the  Falx  tenfe  and  forms  a floor  or  vault 
over  the  Cerebellum,  which  prevents  the  Brain  from  prefling  up- 
on it. 

III.  The  Fai.x  Minor,  or  Septum  Cerebelli,  which  is  placed 
between  the  Lobes  of  the  Cerebellum.  It  defcends  from  the 
underand  back-part  of  the  Falx  in  themiddle  of  the  Tentorium, 
adheres  to  the  inferior  Longitudinal  Spine  of  the  Os  Occipitis, 
and  terminates  infenfibly  at  the  edge  of  the  Foramen  Magnum 
of  that  Bone. 

Betides  the  Procefles  of  the  Dura  Mater  already  defcribed, 
there  are  four  of  inferior  confideration,  two  of  which  are  fituated 
it  the  fldes  of  the  Sella  Turcica  and  two  at  the  edges  of  the  Fora- 
mina Lacera. 

Several  other  Procefles  nafs  out  at  the  different  openings  of 
he  Cranium,  to  be  connected  to  the  Pericranium,  or  to  accom- 
pany the  Spinal  Marrow  and  Nerves  : — Thele  of  the  laft  defcrip- 
:ton  fhall  be  afterwards  taken  notice  of. 

Tiie  Arteries  of  the  Dura  Mater  are  derived  partly  from  the 
External  Carotids,  and  partly  from  the  internal  Carotids  and 
Vertebrals. 

The  Veins  of  this  Membrane  are  of  two  kinds.  One  fet  of 
them,  like  the  Veins  in  other  parts  of  the  body  accompany  the 
Arteries  ; — the  others  are  termed  Sinufes  and  differ  from  Veins 
only  in  this,  that  they  are  of  a triangular  Figure,  and  inclofed 
in  a doubling  of  the  Dura  Mater,  which  is  fo  tenfe  over  them, 
as  to  become  affefled  in  confequence  of  the  preflure  from  fur- 
rounding parts. 

In  the  bottom  of  the  Sinufes  are  fmall  Tranfluerfe  chords  ter- 
med Chorda  Wilisii,  which  may  add  a little  to  their  ftrength,  and 
afllft  in  preventing  them  from  being  too  much  diftended. 

The  Sinufes  lerve  to  carry  the  Blood  from  the  Brain,  and  con- 
vey it  to  the  Veins  of  the  Neck,  for  which  purpofe  they  are  pro- 
perly fitted,  their  covering  from  the  Dura  Mater  giving  them 
ftrength,  and  their  frequent  communications  preventing  congef- 
tiou. 


.12 


1 be  Principal  Sinuses  are, 

I.  The  Superior  Longitudinal  Sinus,  which  begins  at 
the  Crilta  Galli  of  the  Ethmoid  Bone,  runs  along  the  upper 
edge  of  the  Falx,  becomes  gradually  larger  in  its  progrefs,  and 
terminates  in  the  Lateral  Sinules. 

II.  TheToRCULAR  Herophjli,  or  fourth  Sinus  of  the  An- 
cients; the  term  Torcular  is  applied  to  it  from  the  fuppofition 
that  the  Blood  is  fqueezed  in  that  Sinus  as  in  a Wine  prefs. — ■ 
It  is  chiefly  formed  of  the  Vena  Galeni,  runs  between  the  Falx 
and  Tentorium,  and  and  terminates  with  the  former  Sinus  in  the 
beginning  of  the  Lateral  Sinufes. 

III.  The  Two  Lateral  Sinuses,  which  are  formed  by 
the  Longitudinal  and  Torcular  Sinufes,  run  in  depreflions  of  the 
Occipital  and  Temporal  Bones,  firft  tranfverfely,  then  in  a 
winding  di  reftion  downwards,  and  terminate  at  the  Bafe  of  the 
Cranium,  in  the  beginning  of  the  Internal  Jugular  Veins. 

Befides  the  Sinufes  mentioned  above,  feveral  others  of  lefs  con- 
fideration  will  be  pointed  out  in  the  particular  defcription  of  the 
-Veins. 

The  Nerves  of  the  Dura  Mater  are  fo  very  minute,  that  they 
have  not  as  yet  been  dillinftly  traced,  and  it  is  found  to  poflefs 
very  little  fenfibility  in  the  found  date. 

Upon  the  fde  of  the  fuperior  longitudinal  Sinus,  and  contigu- 
ous parts  of  the  Brain,  there  ar t numerous  fmall  Granulations, 
of  a vohitijh  colour,  called  Glandules  Pachioju. 

Befides  thefe  Granulations,  there  are  others  of  the  fame  name, 
of  a Flejhy  colour,  fi tainted  on  certain  parts  of  i he  outer  Surf  ace  of 
the  Dura  Mater,  and  frequently  proje&ing  fo  much  as  to  form 
deep  pits  in  the  Skuil. 

The  nature  of  thefe  Granulations  is  ftill  unknown, — By  i'ome 
fhev  have  been  fuppofed  to  belong  to  the  Lymphatic  Syftem. 

The  Tunica  Arachnoidea,  named  from  its  cob-web  ap- 
pearance, is  an  exceedingly  thin,  tender,  and  tranfparent  Mem- 
brane, in  which  no  vefl'els  have  been  hitherto  obferved. 

It  is  fpread  uniformly  over  the  Surface  of  the  Brain,  ir.clo- 
fing  all  its  Convolutions,  without  insinuating  itfelf  between  any' 
of  them. 

At  the  upper  part  of  the  Brain,  it  adheres  fo  clofely  to  the  fub- 
jacent  Coat  by  fine  Cellular  Subfiance,  that  it  can  fcarcely  be 
Separated  from  it  ; but  in  diffeient  parts  of  the  Bafe  of  the  Brain, 
■particularly  about  the  Tuber  Annulare  and  Medulla  Oblongata, 
it  is  merely  in  cor.tafi  with  the  Membrane  under  it,  and  may 
readily  be  railed  from  it  by  the  aflifiance  of  the  Blow-pipe. 

The  Tunica  Arachnoidea,  like  the  Cuticle,  covers  and  de- 
fends the  parts  under  it. 

The  Pi  a Mater,  named  from  its  tendernefs,  is  fomewhat  of 
i the  nature  of  the  former  covering,  but  is  extremely  Vafcular 


13 


It  covers  the  Brain  in  general,  enters  double  between  all  its  . 
Convolutions,  and  lines  the  diff  rent  Civities  called  Ventricles. 

It  ferves  to  contain  and  fup  to  t the  VelTVIs  of  the  Brain,  and 
allows  them  to  divide  into  luch  minute  part-,  as  to  prevent  the 
Blood  from  entering  the  tender  Subttance  of  this  Vifcus  with  too 
great  force. 

The  Arteries  of  the  Pia  M ter  are  the  fame  with  thofe  of  the 
Brain  and  ire  derived  from  the  Imernai  Carotids  <tnd  Vertebrals. 

The  fains  differ  m no  ref peri  from  thofe  of  the  other  Vifcera, 
exceotin  ; in  this,  that  they  do  not  accompany  the  Arteries. 

The  Bran  ts  J vide!  into  Cerebrum,  Cerebellum,  Tuber  An- 
nulare and  Medulla  Oblongata. 

Cerebrum. 

The  Cereb:-um  is  (ituated  in  the  upper  part  of  the  Cranium, 
which  u compleely  fills. 

It  s div  de  l into  two  halves,  termed  Hemifpberes,  which  are 
fepn rated  from  each  other  by  the  Falx. 

Each  of  t ie  Hemfpheres  is  of  an  oval  form,  or  they  fome- 
whatrelem  ole  an  egg  cut  into  two  longitudinal  helves.  The  in- 
ner tides  are  Hit,  the  upper  and  outer  parts  convex,  and  the  un- 
der Surface  nebular. 

Tne  under  S i face  is  divided  into  tvjo  Anterior,  tvjo  Lateral, 
and  ttvo  Pojh’-'ior  Lobes , or  ProceJJ'es. 

The  Anterior  Lobes  zre  limited  m the  fore-part  of  the  Bafe  of 
the  Cranium. 

The  Lateral  or  Middle  Lobes,  are  lodged  in  the  FofLe  formed 
by  tiie  feinpor  .1  and  Sphenoid  B ones. 

Th e Pole  ior  Lobes  are  placed  over  the  Cerebellum,  and  are 
fepar.ited  from  t by  the  Tentorium. 

Between  the  Anterior  and  Lateral  Lobes,  there  is  a Fwrovj 
formed  by  the  Anterior  Clinch'd  Precedes  of  the  Sphenoid  Bone, 
which  has  been  termed  Foffa,  or  Fiffura  Magna  Siruvii. 

Tne  Surface  of  the  Brain  is  divided  into  many  turnings  or 
windings,  termed  Circumvolutions , which  run  in  various  direc- 
tions, and  are  of  different  iizes  and  lengths  on  different  parts  of 
the  Brain. 

The  Circumvolutions  are  every  where  connected  to  the  Pia 
Mrtei  by  an  infinite  number  of  final!  Veifcls,— called  by 
Ruysci-i,  To/nentum  Cerebi , — which  run  into  the  Subffunce  of 
the  Brain  ; as  may  be  readily  leen,  upon  ieparaung  the  Circum- 
volutions a li  tie  from  each  other. 

Between  the  Hem  ipneies  a white  Subftance  is  obferved,  cal- 
led Corpus  Cailofum,  from  its  being  a little  firmer  than. the  reft  of 
the  Brain. — It  goes  acrofs  the  Biain,  under  the  Falx,  and  is 
merely  a continuation  of  Medullary  Subilance,  running  hort- 

VOL,  II.  B 


14 


zontally,  and  joining  the  twb  Tides  of  the  Hemifpheres  to  each 
other. 

In  the  middle  of  the  Corpus  Callofutn  there  is  a longitudinal 
Raphe,  with  a Medullary  Cord  on  eaci:  fide,  from  which  many 
tranfverfe  Freaks  iffue.  Thefe  Cords,  like  the  Corpus  Cal- 
lofum  itfelf,  become  gradually  broader  towaids  the  poller i or  ex= 
tremity. 

An  horizontal  Seflion,  a little  above  the  middle  height  of  the 
Brain,  or  upon  a level  with  the  Corpus  Callolum,  Thews  the  di- 
vision of  the  Subfiance  of  the  Brain  into  outer  or  inner,  or  Cor- 
tical and  Medullary  parts. 

The  outer  Subllance  is  termed  Ciueritious,  from  its  being  of 
a greyijlj  or  ajh  colour, — though  a little  tinged  with  brown; — 
and  Cortical,  from  its  furrounding  tire  inner  part  of  the  Brain,  as 
the  Bark  does  the  Pith  cf  a Tree 

It  is  termed  by  Jome  Authors  Glandular,  and  by  others  Secre- 
tory, from  a fuppofition  that  a Fluid  was  fecreied  in  ir. 

The  Ciueritious  Snbfxance  covers  the  Brain  in  general,  and  en- 
ters deep  between  its  Convolutions,  is  of  a foft  confidence,  and 
6*inpofed  of  numerous  final  1 Vefils  carrying  red  Blood  ; but 
it  is  uniform,  and  without  any  appearance  of  a Fibrous  texture. 

The  inner  SubFance  is  termed  JVhite  or  Medullar . , and  is  con- 
fidcred  as  giving  origin  to  the  different  Nerves.  It  has  been  by 
fome  called  Excretory,  having  been  ftippofed  to  be  formed  of  hol- 
low Tubes  continued  fiom  the  Veflels  of  the  Cortical  part; — 
but  no  Cavit  es  have  ever  been  obl'erved  in  the  loft  Fibres  of 
which  it  is  computed. 

It  is  greater  in  quantity,  and  fome  what  firmer  in  texture,  than 
the  Ciueritious  SubFance,  and  is  i'o  intimately  connected  as  to 
appear  to  be  a continuation  of  it. — The  fort  Fibres  or  Freaks  of 
the  Medullary  Matter,  run  in  general  in  a parallel  and  tranfverfe 
dire£tion. 

In  many  parts  of  the  Ciueritious  Subfiance,  Medullaiy  Mat- 
ter appears  ; and,  on  the  o ntrary,  in  different  parts  of  the  Me- 
dullary Subllance,  Ciner  tious  Matter  is  found  ; the  two  being 
frequently  blended  together  in  the  form  of  Freaks.  See  Monro 
on  Nervous  Syjfem. 

The  Centrum  Ovale  of  Vieussens.  This  is  the  Medullary 
Subftance  of  the  Brain,  forming  a kind  of  Nucleus,  which  is 
feen  after  removing  the  Cineritious  Subllance,  and  all  the  Me- 
dullary parts  mixed  with  it,  which  be  between  tile  Cortical  Con- 
volutions. 

. To  obtain  a proper  view  .of  the  Centrum  Ovale,  the  .Nucleus 
ought  to  be  cut  in  fuch  a manner  as  to  prelerve  the  Corpus  C:d- 
lofum,  and  the  fame  convexity  with  that  of  the  general  convexity 
of  the  Brain. 


15 


The  Centrum  Ovale  forms  an  arch  or  roof  over  the  two  Lateral 
Ve.  it  ■ , .he  - ii  er  part  of  this  roof,  which  is  i'mooth  and 

unifor l . . c M'.nic'.'US  .lie  upper  part  of  thele  Ventricles. 

Vi..u  s-::  ,s  < n lidered  the  Centrum  Ovale  as  the  great  Dif- 
pc-..  cj  tb  An’ null  Spirits. 

f Vr  r R : c l £ s tire  Brain  are  four  in  number,  two  of 
which  are  er.iir.t  Lateral. 

The  four  Veil  ■ icier  nave  their  tides  contiguous  to  each  other, 
are  chietiv  to-, nr:,  of  Medullary  Matter,  and  are  lined  with  a 
continuation  •■=  P'u  Mater,  winch  d. tiers  from  that  covering 
the  e rertir  Surface  of  the  Brain,  m having  fewer  \elTels  dif- 
peried  upon  it. 

They  are  conftantiv  moiftened  by  a Fluid,  which  prevents 
their  uppofite  fides  from  adhering  to  each  other. 

The  uf  of  the  Ventricles,  like  many  other  parts  of  the  Brain, 
is  (till  unknown. 

The  Lateral , formerly  called  Superior  Ventricles,  are  fituated 
in  the  Hemilpheres,  one  in  each,  and  run  Horizontally  in  the  fame 
direction  with  he  Hemilpheres  tlrenrlelves. 

They  are  of  an  irregular  form,  hying  under  the  Centrum 
Ovale,  and  have  each  three  winding  corners,  compared  to  Rani’s 
Horns,  which  are  therefore  called  Cornua. 

The  Anterior  Cornua  are  feparated  only  by  the  Septum  Luci- 
dum. 

The  Poferior  Cornua , called  alio  Digital  Cavities , are  at  a 
considerable  diftance  front  each  other,  but  approach  nearer  at 
their  pointed  extremities  ; while  the  inferior  Cornua,  the  begin- 
ning of  which  is  feen,  run  downwards  arid  forwards,  and  termi- 
nate in  the  Lateral  Lobes  of  the  Brain. 

In  each  of  thePofterior  Cornua  there  is  an  Elongation,  which 
terminates  in  a point,  and  i-s  called  Ergot  by  the  French,  from 
its  refemblanee  to  the  Spur  of  a Cock  ; or,  Hippocampus  Minor, 
from  its  fimilarity  to,  and  connection  with,  the  l'ttbftance  termed 
Hippocampus  Major. 

In  the  fore-part  of  the  bottom  of  the  Lateral  Ventricles,  are 
two  large  Eminences,  called  Corpora  Striata,  which  become 
gradually  narrower,  and  recede  from  each  other  at  their  polferior 
extremities. 

The  Structure  of  thefe  is  Cineritious  externally,  and  mixed 
with  Medullary  Striae  within,  fome  of  which  form  large  Tranf- 
verfe  Medullary  Arches,  and  others  run  more  in  a ftraight  direc- 
tion. 

Between  the  pofterior  parts  of  the  Corpora  Striata,  arelituated 
the  Thalami  Nervorum  Opticorum,  which  have  a roundifh  form 
and  Medullary  Surface,  and  are  of  a Striated  appearance  within, 
bat  the  Striae  are  Id's  dtftinft  than  in  the  Corpora  Striata. 


16 


Upon  the  Suiface  of  thefc  Bodie',  there  are  fmal!  Eminences  or 
'Tubercles,  fome  of  which  are  placed  upon  their  fuperior,  and 
oihers  upon  their  inferior  extremities. 

The  inner  parts  of  the  Thalami  are  flat  and  contiguous,  and 
above  they  aie  fo  clofely  conne&ed  as  to  form  one  continued  Sur- 
face; called  CommiJJura  Mollis  of  the  Optic  Thalami. 

The  poflerior  parts  of  the  Thalami  turn  downwards  and  out- 
waids,  after  which  they  aie  elongated,  to  form  the  two  white 
Cords,  called  Traftus  Optici. 

In  the  Groove  between  the  Corpora  Striata  and  Thalami,  there 
is  a Medullary  Band  on  each  fide,  called  Centrum  Semicirculare 
Gimihum  oj  V i e u s s li  n s , or  Tania  Setnicircularis  c/Haller,  or 
fimply  Tcrnia. 

Over  the  Thalami  is  placed  the  Choroid  Plexus , — named  from 
its  being  compofed  of  a Chorus  of  Vefltls  and  Membranes. 
It  is  a fine  Vaf'cular  Web,  confining  of  fmall  ramifications  of 
Aiteries  and  Veins,  conin&ed  by  the  Pia  Mater,  and  ip  read  upon 
the  Surface  of  the  Thalami.  and  fome  of  the  adjacent  parts. 

The  Choroid  Plexus  frequently  contains  numerous  round 
Globules,  relembling  Hydatids,  which  have  been  confidered  by 
fome  Authors  as  Lymphatic  Glands. 

Under  the  Raphe  of  the  Corpus  Callofum,  is  placed  the  Septum 
Lucidum,  which,  when  viewed  laterally,  is  obferved  to  be  broad 
before,  curved  at  its  edge,  and  to  become  gradually  narrower  to- 
wards its  polfer  or  extremity. 

It  is  connected  above  to  the  Corpus  Callofum,  below  to  the 
Fornix,  and  foims  a d i ft i n 6b  partition  between  the  lateral  Ventri- 
cles. 

It  is  formed  of  two  Cineritious  and  Medullary  Laminae,  more 
or  lefs  feparated  from  each  other  at  their  fore-part,  by  a fmall 
Cavity,  called  Fiffure , or  Fojja  of  Sylvius  or  Sinus  of  the  Sep- 
tum Lucidum,  which,  however,  dees  not  communicate  with  the 
Lateral  Ventricles,  though  in  feme  fubjefts  it  reaches  a confider- 
able  w.y  backwards,  and,  as  well  as  the  other  Cavities  of  the 
Brain,  has  been  found  full  of  water  in  Hydrocephalous  cafes. 

Under  the  Septum  Lucidum  is  placed  the  Subftar.ee  which  has 
been. compared  in  fhape  to  a Vault  by  the  Ancients,  and  from 
that  has  obtained  ihe  name  of  Fornix. 

The  Fornix  is  merely  a continuation  of  the  Corpus  Callofum, 
and  forms  a fort  of  hollow  Ceiling,  with  four  Pillars  called  Cru- 
ra, or  Cornua,  from  then  winding  diieftion,  of  which  there  are 
two  anterior  and  two  polienor. 

The  two  /. interior  Crura  are  fhort,  run  clofe  together,  and 
become  enlarged  at  their  inferior  parts.  The  two  FoJIeiior  Cru- 
ra are  long,  ounfiderably  diftam  from  each  other,  and  form  Cur- 
vatures which  correlpond  with  the  couife  of  the  Inferior  Cornua 
of  the  Lateral  Ventricles. 


That  part  of  the  Crura  Fornicis  lying  in  the  Inferior  Cornua 
of  thefe  Ventricles,  forms  thin  borders,  getting  the  name  of  Cor- 
pora Fimbriata  ; but,  according  to  the  Vic  D’Azyr,  they  are 
more  properly  termed  Tcenia  Hippocampi,  from  being  united 
with  the  great  Hippocampus. 

The  body  of  the  Forn  x is  narrow  anteriorly,  and  becomes 
conhderably  broader  behind,  where  it  is  incorporated  with  the 
Corpus  Callolum. 

The  under  Surface  of  the  pofterior  part  of  the  body  of  the  For- 
nix, is  impreffed  with  numerous  tranfverfe  and  oblique  Line?* 
which  have  been  called  FJalterium,  or  Lyra,  from  tome  refem- 
blar.ce  they  bear  to  the  ancient  mufical  inftruments  of  thele 
names. 

The  body  of  the  Fornix  is  joined  above  to  the  Septum  Luci- 
dum  ; below  it  is  connected  to  the  Thalami  Optici  by  a Vafcu- 
lar  Membrane,  called  Tela  Choroidea,  which  fpreads  over  the 
Thalami,  and  unites  the  Choroid  Plexus  of  the  Lateral  Ventri- 
cles. 

The  Pedes  Hippocampi,  Great  Hippocampus,  ovCor- 
NUA  Ammonis, — named  from  a fuppofed  relemblance  to  thefe 
parts, — are  two  Medullary  Eminences,  which  arife  from  thefides 
of  the  pofterior  exti  emity  ot  the  Corpus  Callofum,  and  are  lituated 
in  the  inferior  Prolongations  of  the  Lateral  Ventricles. 

They  run  through  the  whole  extent  of  the  Prolongations,  firft 
behind,  then  at  the  outer  part  of  the  pofterior  Pillars  of  the 
Fornix,  and  are  fo  intimately  connected  witli  them,  that  they 
have  been  considered  by  fome  Authors  as  forming  part  of  the 
Pillars  thcmfelves. 

They  are  final  1 at  their  origin,  from  which  they  continue  to 
mcreai'e  to  their  farther  extremity. 

Like  the  greater  pait  of  the  Ventricles,  they  are  covered  exter- 
nally with  a Medullary  Lamina; — internally  they  are  found  to 
coniift  of  Medullary  and  Cineritious  Laminae,  of  a convoluted 
appearance. 

At  the  inner  edge  of  the  Pedis  Hippocampi,  there  is  a plaited, 
fer rated,  or  indented  Margin,  which,  in  the  generality  of  (Quad- 
rupeds, is  much  larger,  in  proportion  to  the  fize  of  the  Brain, 
than  it  is  in  Man. — The  refemblance,  however,  to  the  human 
kind,  in  the  ftructure  of  this  particular  part  of  the  Brain,  is 
more  finking  in  the  Ape  than  in  any  other  Quadruped. 

In  the  bottom  of  the  Lateral  Ventricles,  behind  the  anterior 
Crura  of  the  Fornix,  and  before  the  meeting  of  the  Choroid 
Plexufes  of  thele  Ventricles,  below  the  anterior  part  of  the  body 
of  the  Torn ix,  and  over  the  fore-part  of  the  third  Ventricle,  there 
is  a Hole,  ot  an  oval  form,  by  which  the  Lateral  Ventricles 
communicate  freely  with  each  other.  See  Monro’s  Obf.  on 
Nerv.  Syjl.  1783,  and  Treat  if e on  the  Brain,  1797. 

Vol.  II.  B 2 


IS 


After  dividing  and  turning  back  the  Fornix,  another  commu- 
nication from  the  above  paffage  is  found,  called  Foramen  Com- 
mune Anterius,  Vul-va,  or  Iter  ad  Infundibulum  ; but  properly. 
Iter  ad  Tertium  Ventriculum,  or  Paffage  to  the  third 
Ventricle. 

Between  the  Commiffura  Mollis  of  the  Optic  Thalami,  and 
Subftance  callad  Pineal  Gland,  there  is  a Imall  paffage  termed 
Anus,  or  Foramen  Commune  Pojlerius,  which  has  been  l'uppofed 
by  fonie  Authors  to  form  a communication  between  the  back-part 
of  the  third  Ventricle  and  Lateral  Ventricles  ; but  it  is  complete- 
ly fnut  up  by  the  Tela  Choroidea,  and  alfo  by  the  Fornix,  which 
adheres  cloiely  to  tins  Membrane. 

The  Third  Ventricle  is  in  form  of  a deep  Fiffure,  placed 
between  the  inner  ends  ol  the  Thalami  Optici,  having  the  Com- 
miffura Mollis  of  thele  Thalami  fi'uated  above,  the  Crura  Cere- 
bri below,  and  the  bodes  of  the  Thalami  on  each  fide. 

The  Infundieulum  is  a paffage  of  confiderable  fize,  of  a 
Cineritlous  and  Medullary  ltru&ure,  which  leads  downwards 
and  forwards,  gradually  eontrafting,  and  becoming  folid  at  its 
under  end,  where  it  terminates  in  the  Glandula  Pituitaria  and 
thus,  contrary  to  the  opinion  of  the  Ancients,  preventing  the  paf- 
fage of  any  Pituitous  Fluid  from  it  to  the  Nofe. 

The  Glandula  Pituitaria  is  of  an  oval  form,  about 
the  fize  of  a Field-Bean,  lodged  in  the  Sella  Turcica,  and  fur- 
jounded  by  a doubling  of  the  Dura  Mater. 

On  the  outlide  it  is  of  a brownifh  colour,  being  formed  of  Ci- 
neritious  Matter  5 it  is  whiter  within,  where  it  is  mixed  with 
Medullary  Subftance. 

The  Glandula  Pituitaria  was  formerly  fuppofed  to  abforb  a 
Fluid  from  the  Infundibulum,  and  trjmfrnit  it  to  the  Nofe.  It 
has  been  already  mentioned,  however,  that  the  Infundibulum  is 
impervious;  and  the  real  ufe  of  this  Gland,  as  well  as  of  the 
other  Tubercles  of  the  Brain,  feems  ftill  unknown. 

At  the  fore-part  of  the  third  Ventricle,  and  immediately, be- 
foie  the  Anterior  Crura  of  the  Fornix,  there  is  a white  Medul- 
lary Cord,  which  runs  tranfverfely  through  the  Corpora  Striata, 
and  has  the  name  of  Com  mis  sura  Cerebri  Anterior. 

At  the  back-part  of  the  third  Ventricle,  and  under  the  root  of 
the  Pineal  Gland,  there  is  another  Cord  fimilar  to  the  former, 
but  fhorter,  called  Commissura  Cerebri-  Posterior.  The 
Comtmjjune  Cerebri  aflift  in  uniting  the  two  ftdes  of  the  Brain  to 
which  they  are  fixed . 

From  the  under  and  back-part  of  the  third  Ventricle,  there  is 
a Paffage  which  leads  to  the  fourth,  under  the  name  of  Iter 
ad  Quart um  Ventriculum,  Canalis  Medju{,  or  Aquaduc- 
tus  Sylvji. 


After  the  pofterior  part  of  the  Fornix,  and  theTela  Cnoroidea 
to  which  it  adheres,  have  been  removed,  there  ap:  ear  at  the 
back-part  of  the  third  Ventricle,  behind  the-Thalami,  and  over 
the  Iter  a Tertio  ad  Quartum  Ventriculuni,  the  Nates  and  Tes- 
tes, or  Tubercula  Quadrigemin  a,  and  Pineal  Gland. 

The  Nates,ol'  Tubercula  Quadngemina  Anterior  a,  are  placed 
uppermoft,  and  are  of  a rounder  form  titan  the  Testes,  or  Tuber- 
ciila  £>uadrige?nina  Foderiora, — -which  he  immedia.ely  below  the 
former.  — Tite  Teftes  are  broader  from  one  iide  to  the  other  than 
from  top  to  bottom,  and  of  a white  colour. 

A longitudinal  Section  Ihews  the  Tuoercula  to  be  covered  ex- 
ternally with  a thin  Medullary  Lamina,  and  to  be  Cineritious 
within. 

in  Man  they  are  more  nearly  of  an  equal  lize  than  in  Quad- 
rupeds, as  in  the  Ox,  Sheep,  &c.  in  which  the  Nates  are  large, 
round,  and  of  a brown  colour,  and  the  Teftes  fmail  and  long. 

Over  the  Nates,  and  under  the  back-part  of  the  Fornix,  is 
placed  a linall  body,  cf  a Cinentious  nature,  about  the  lize  of  a 
Garden-Pea,  and  of  a Conoid,  figure,  called  Glandula  Pi- 
ne alis,  from  its  refemblance  in  fhape  to  a Pins  or  Fir  Lons. 

In  confequence  of  being  always  prefent,  and  l’eldom  found  in 
a dil’eafed  tfate,  it  has  been  celebrated  by  Des  Cartes,  as  be- 
ing, according  to  his  fuppolition,  th s- Seat  of  the  Soul. 

The  Pineal  Gland  is  fixed  at  its  root  to  the  Comimffura  Cere- 
bri Pofterior,  and  fends  out  tnxo  long  Medullary  Peduncles,  or 
Foot-Jlalks,  to  be  fixed  to  the  upper  anti  inner  fide  of  the  Thaiumi 
and  to  the  Anterior  Crura  of  the  Fornix. 

Near,  or  in  the  Subftance  of  the  Pineal  Gland,  fmail  Calcare- 
ous Concretions  are  fometimes  found,  called  by  Soemmering, 
Acer<vulus  Cerebri,  from  their  being  generally  found  colledled  in 
a heap. 

They  do  not  appear  to  be  the  effects  of  difeafe  ; nor  are  they 
met  with  till  after  the  age  of  Puberty. 

Cerebellum. 

The  Cerebellum  is  fituated  in  the  Inferior  FofTse  of  the  Occi- 
pital Bone,  under  the  Pofterior  Lobes  of.the  Brain,  and  is  fepa- 
rated  from  thefe  Lobes  by  the  Tentorium. 

It  is  fomevvliat  of  a roundifli  form,  though  a little  broader  from 
one  iide  to  the  other  than  from  before  backwards.  It  is  only 
about  a fifth  or  fixth  part  of  the  fize  of  the  Cerebrum,  and  much 
iimpler. 

It  is  divided  behind  by  the  Falx  Minor  into  two  Lobes  or  He- 
mifpheres,  but  lias  no  reparation  above  like  the  Brain. 

Its  Surface  is  divided  into  numerous  Circumvolutions,  which 
from  arches,  decufl'ating  each  other  in  many  parts,  at  (harp  an- 


20 


Tlie  Cii'cumvolutions  run  chiefly  in  a Lateral  direction,  and 
are  formed  of  Laminae,  with  deep  Sulci  between  them,  into 
which  as  in  the  Brayi,  the  Pia  Mater  infinuates  itfelf,  which 
may  be  leadily  leen  by  making  a punilure  into  the  Arachnoid 
Coat,  and  blowing  in  air  till  it  diltend  the  Cellular  Subftance, 
and  leparate  the  Coats  from  each  other. 

It  nas  two  middle  Eminences,  called  Appendices  Vermifor- 
mes,  from  their  relemblance  to  Earth  Worms,  one  of  which  is 
fituated  anteriorly  and  fuperiorly,  the  other  interiorly  and  pof- 
teriorly. 

Each  of  the  Lobes  of  the  Cerebellum  is  again  divided  into 
Monticuli,  or  Lobules,  which  have  different  names  according  to 
their  relative  lituations,  cormtihons  with  other  parts,  &c.  They 
vary  a little  in  the  different  Subjeits,  but  are  befl  ddUnguilhed 
from  the  direction  of  their  Convolutions. 

The  Subltance  of  the  Cerebeilum  confifts  of  Cineritious  and. 
Medullary  Matter,  as  in  the  Ceiebrum  ; but  the  Cineritious 
bears  a greater  proportion  to  the  Medullary  in  the  former  than  in 
the  latter. 

When  the  Ccrebellunj.  is  cut  in  a vertical  direition,  the  Me- 
dullary, part  is  then  found  to  bear  a linking  relemblance 
to  the  branching  of  the  Ih  ub  called  Arbor  Vita,  from  which 
circumftance  it  has  obtained  the  name  of.th's  fhrub. 

When  cut  in  dices  nearly  parallel  to  the  Baie  of  'he  Brain,  the 
Medullary  Subilance  appears  in  Laminae,  coi  refpontling  to  thole 
of  the  Surface  of  the  Cerebellum;  and  when  cut  to  a conlidera- 
ble  depth,  there  is  a Centrum  MeduJlare  uniting  the  Lateral  Lobes 
as  in  the  Brain. 

Between  the  Cerebellum;  the  under  part  of  the  Tuber  Annu- 
lare, and  upper  part  of  the  Medulla  Oblongata,  the  Fourth  Ven- 
tricle is  fituated,  which  extends  from  the  Eminences  called  t Teftes 
to  the  posterior  inferior  Notch  of  the  Cerebellum. 

A little  lower  than  the  Teltes,  the  Ventricle  becomes  wider, 
and  forms  an  angle  behind,  from  which  again  contrails,  and 
becoming  narrower  and  pointed  below  like  a writing-pen,  is  cal- 
led Calamus  Scriptorius . 

Over  the  under  end  of  the  Aquteduihis  Sylvii,  and  upper 
part  of  the  fourth  Ventricle,  there  is  a thin. Medullary  Lami- 
na, called  Vabvula,  but  properly  Velum  Vieussknii. 

At  the  Tides  of  the  Velum  Vieufl'enii  there  are  two  Medullary 
trails,  called  Procejjus  adFef.es,  or  Columns  Vabvula:  Vieus- 
SEN1I. 

The  under  end  of  the  Ventricle  is  found  to  be  (hut  up  by  its 
Choroid  Plexus,  which  prevents  any  communication  belweer 
tins  Cavity  and  that  of  the  Spine. 


21 


UNDER  SURFACE  OF  THE  BRAIN. 

Near  the  middle  of  the  Bafeof  the  Brain,  and  between  its  La- 
teral Lobes,  there  are  two  l'mall,  round,  white  bodies,  termed 
Emin  entice  Mammilai  es,  or  Corpora  Albicantia , Medullary 
without,  Cinerit.ous  within,  miitaken  by  lame  Authors  for 
Glands. 

In  the  Corpora  Albicantia,  various  Medullary  Strata  termi- 
nate, which  come  from  different  parts  of  the  Brain. 

Immediately  before  the  Corpora  Albicantia,  two  large  white 
Cords  are  obferved,  called  Crura,  or  Pedunculi  Cerebri,  or  Cru- 
ra Anteriora  Medullas  Oblongatcr,  which  arife  from  the  Medul- 
lary Sublfance  of  the  Brain,  and  gradually  approach  each  other 
in  their  courfe,  tjll  they  unite  with  the  Tuber  Annulare. 

Their  Surface  is  fiat,  and  compol'ed  of  diltinCt  Medullary 
Fibres  ; internally  they  are  compol'ed  of  a Mixture  of  CLneriti- 
ous  and  Medullary  Matter,  the  former  of  which  being  of  a darker 
colour  at  one  par  ticular  part  than  in  any  other  of  the  Brain,  has 
been  ter  med  Locus  Niger  Crurum  Cerebri. 

Between  the  Crura  Cerebri  and  Corpora  Albicantia,  there  is  a 
Cineritious  Sublfance,  called  Pons  Tarjni,  which  joins  thefe 
two  bodies  of  the  oppofue  lides  together,  and  afillfs  in  forming 
the  bottom  of  the  third  Ventricle. 

From  the  Medullar  y part  of  the  Cerebellum,  which  forms  the 
trunk  of  the  Arbor  Vitas  two  white  cords  arile,  under  the  name 
of  Crura  Cerebelli,  or  Crura  Pcfrcriora,  or  Pedunculi  Cerebetti, 
which  unite  with  the  Crura  Cerebri,  to  compote  the  Tuber  An- 
nulare, or  Pons  V arolii,  l’o  named  from  forming  a Ring  or 
Bridge  over  the  Crura.  This  ring  is  intimately  incorporated 
with,  and  formed  by  thefe  Crura. 

The  Tuber  Annulare  is  fituated  over  the  back  part  of  the  body 
of  the  Sphenoid  and  Cuneiform  Procefs  of  the  Occipital  Bone. 
Many  tranlverfe  Itreaks  run  on  its  Surface,  and  it  is  divided 
into  two  lateral  parts  by  a longitudinal  depreffion,  occafioned  by 
the  fituation  of  the  Vertebral  Artery, 

At  the  tore  and  back  parts  of  the  Tuber,  are  the  Poratnina 
Caeca  Anterius  et  Pcjlerius,  the  former  placed  between  the  third, 
and  the  latter  between  the  lix  h Pair  of  Nerves  : Thefe  two  Fora- 
mina penetrate  only  a little  way  at  the  edges  of  the  Tuber,  and 
receive  a Plexus  of  Veflcls, 

In  the  Sublfance  of  the  Tuber,  there  is  much  Cortical  Matter, 
which  is  formed  inio  Stria,  running  in  different  directions. 

Continued  from  the  luber,  the.e  is  a large  Sublfance  in  form 
of  an  inverted  Cone,  which  extends  to  the  Foramen  Magnum  of 
the  Occipital  Bone,  under  the  name  of  Medulla  Oblongata. 

* Upon  the  Surface  of  the  Medulla  Oblongata,  two  iinall  Emi- 
nences appear,  which  run  longitudinally  and  contiguous  to  each 


other  and  from  their  fltape  have  the  name  of  Corpora  Pyramida- 
lia,  or  Eminently  Pyramidales. 

Between  rhe  Corpora  Pyramidalia,  there  is  a deep  F Ifure,  into 
which  the  Pia  Mater  penetrates,  and  where  Blood -v uld s pafs 
into  the  interior  part  ot  the  Medulla. 

At  the  outfide  of  the  for  met  Eminences,  are  two  others,  !ome- 
wbat  of  the  form  of  Olives,  (V.  in  which  they  arc  termed  Corpora 
Oltvaria,  or  Eminently  Olivares. 

More  externally  than  their,  are  two  other  Eminences,  Iefs 
evident  than  the  former,  which  hive  been  defer  died  by  iome  Au- 
thors by  the  name  of  Corpora  Pyramidalia  Lateralia. 

The  Medulla  Oblongata  is  divided  into  two  lateral  portions, 
by  an  anterior  and  polh rior  Failure.,  and  the  two  portions  are 
formed  of  Medullary  Matter  without,  and  a large  proportion  of 
Cinei  itious  Matter  internally,  and  joined  together  by  Medullary 
Fibres. 

The  Brain  is  the  Grand  and  Primary  Organ  of  Scnfe,  with 
which  the  Mind  is  fuppofed  to  be  moft  immediately  and  intimate- 
ly connected,  and  from  which  the  Nervous  Influence  is  found, 
by  experiment,  to  be  communicated  to  all  the  other  parts  of  the 
Body. 

Origin  of  the  Nerves. 

The  Nerves  arife  from  the  Medullary  parts  of  the  Brain,  fome  • 
in  fol  d Cords,  others  in  feparate  Threads  which  afterwards  unite 
into  Cords  ; and  have  their  name  in  numerical  fucceflion,  accord- 
ing to  their  fituations,  beginning  anteriorly. 

The  Firf,  or  OlfaHory  Pair  of  Nerves,  arife  from  the  back- 
part  of  the  pofterior  lobes  of  the  Brain,  and  run  towards  the  Crifta 
Galli  of  the  Ethmoid  Bone,  over  which  each  forms  a brownilh- 
coloured  Bulb,  from  whence  numerous  fmall  Nerves  are  lent 
off. 

The  Second  Pair,  or  Optic  Nerves,  are  the  continuations  of 
the  Tbalami  Optici.  They  are  united  immediately  betore  the 
Infundibulum,  and  form  an  intimate  intermixture  of  parts,  and 
again  feparate  previous  to  their  palling  into  the  Orbiis. 

The  ’Third  Pair  arife  by  numerous  Threads,  which  are  foon 
collefted  into  Trunks. 

The  Fourth  Pair,  which  are  the  fmalleft  Nerves  of  the  Body, 
arife  behind  the  Teltes,  and  have  a long  and  winding  courfe. 

The  Fifth  Pair,  which  are  the  largeft  Nerves  in  the  Brain, 
have  each  an  anterior  fmall,  and  a pofterior  large  Falciculus, 
which  arifes  from  the  fide  of  the  Tuber  Annulare. 

Tile  Sixth  Pair  arife  from  the  beginning  of  the  Medulla  Ob- 
longata, where  it  joins  the  Tuber  Annulare.  Each  of  the  Nen  cs 
of  this  Pair  has  a fmall  Thread  at  its  inner  part. 


The  Seventh  Pair  arife  from  the  beginning  of  the  lateral  parts 
of  the  Medullary  Oblongata,  and  are  divided  on  each  fide  intq  a 
Portia  Mollis,  afid  Portio  Dura. 

The  Eighth  Pair  arife  by  l'mall  Fafciculi  from  the  Corpora  Oli- 
varia. 

The  Ninth  Pair  of  Nerves  alfo  arife  by  fmall  Fafciculi,  a lit- 
tle below  the  former,  from  ihe  Corpora  P ramidalia. 

The  Origin  of  the  Nerves  will  be  defcribed  at  greater  length, 
in  a fubfequent  part  of  the  Volume. 


>00000000-5*00000000' 


OF  THE  EYE. 


>0' 


The  Eyes,  which  conftitute  the  Organ  of  Vifion,  are  fituated  in 
the  Cavities  of  the  Orbits,  and  are  Unrounded  by  feveral  parts, 
fome  of  which  proteft  them  fiorn  injury,  and  others  aflilf  in  the 
peifoimance  of  their  various  motions. 

The  Orbits  are  formed  of  two  Cones,  fituated  in  the  fore-part 
of  the  Cranium,  with  their  Apices  behind,  their  Axes  in  an 
horizontal  fituation,  and  their  Bafes  turned  obi  queiy  ou  wards. 

Each  of  the  Orb  ts  is  formed  of  different  Procefi'es  of  the  fol- 
lowing Bones,  viz. 

Ttie  upper  part  of  each  Orbit,  by  the  Orbitar  Plate  of  the 
Frontal  Bone; — the  inferior,  by  the  Orbitar  Plates  ot  the  fuperi- 
or  Alaxillary  amt  Malar  Bones  ; — the  internal,  chiefly  by  the 
Orbit ir  part  of  the  Os  Unguis  and  Pars  Plana  of  the  Ethmoid 
Bone; — the  external,  by  the  Orbitar  Piates  of  the  Sphenoid  and 
Malar  B nes ; — the  pofterior,  by  the  Sphenoid  and  Palate  Bones; 
— and  the  anterior  edtre  of  the  Or  it,  by  the  Frontal,  luperior 
Maxillary,  and  Mil  tr  Bones. 

The  Cavities  of  rite  Orbits  are  l ned  with  Produ&ions  of  the 
D nra  Mater,  whi.h  pals  out  at  the  Foramina  Optica  and  Lacera 
and,  at  the  anterior  edges  of  the  Orbits,  join  the  Periotleum  of 
the  Face,  where  they  lupply  the  place  of  Ligaments  to  the  Pal- 
pebrse. 

Supercilia. 

The  Supcrcilia,  or  Eye-B;  ovjs,  which  are  peculiar  to  the  Hu- 
man fpecies,  are  the  arches  of  Hair  iitu-ated  upon  the  Supercilia- 


24 


ry  Ridges  of  the  Frontal  Bone.  The  Hairs  are  placed  obliquely, 
with  their  ro<  ts  towaids  the  Nofe,  and  the  Arches  elevated  a lit- 
tle above  the  reft  of  the  Fore-head,  by  a considerable  quantity  of 
Cellular  Subftance  lying  under  the  Skin. 

Theyaie  moved  in  diffeient  direft  ons  by  the  aflion  of  the 
Frontal  Corru  ator,  and  Orbicular. s Palpebrarum  Mufcles. 

They  are  intended  partly  for  ornament,  and  paitly  as  Shades 
over  the  Eves,  thereby  preventing  them  from  being  injured  by 
extraneous  Mattel,  or  by  too  great  a quantity  of  light.  They 
alio  aftlft  in  ex,  i tiling  the  paflions  of  the  Mind. 

Palpebr^e- 

The  Palpebra,  or  Eye-lids,  are  chiefly  compofed  of  a doubling 
of  the  Skin,  inch ding  part  of  the  Orbicularis  Palpebrarum 
Ivlufcle,  and  the  Cartilages  called  Earfi,  and  forming  angles  at 
the  r ou  er  and  inner  extremities,  termed  Cantbi,  or  Corners  of 
the  Eye. 

The  Upper  Eye-lid  16  the  one  which  moves  principally  in  clo- 
fing  or  opening  the  Eye,  the  under  mut  ing  only  when  the  Eye  lids 
are  fhot  with  uncommon  foi  ce. 

The  motions  of  the  Eye-lids  are  pei  formed  by  the  a£lion  of  the 
Orb’cularis  and  Levitoi  Palpebrarum  Mufcles. 

The  Eve-lids  fei ve  as  Curtains  or  Veil-,  to  defend  the  Eves 
during  lleep  : They  likewife  p event  them  from  being  injured  by 
exti aneotis  objefls,  or  by  too  much  light.  By  their  frequent 
motion  they  increafe  the  lecreiion  of  the  fears,  apply  them  pro- 
perly to  the  Surface  of  the  Eye,  and  condufl  what  remains,  after 
wafhing  the  Eye,  to  the  P'unfla  Lacrymalia. 

Tarsus. 

This  is  a thin  Cartilaginous  Arch,  fituated  in  the  edee  of  each 
Eye  l:d,  that  in  the  upper  one  being  confiderably  broader  than 
the  one  below,  and  each  broader  at  its  middle  than  towards  its 
extremities. 

Their  edges  are  fo  placed,  that  when  the  Eye-lids  are  fhut,  a 
groove  is  left  next  the  Eye  by  which  the  Tears  are  conveyed  to- 
wards the  Nofe. — They  terminate  at  a little  diltance  front  the  in- 
ner angle  of  the  Eye. 

They  ferve  to  keep  the  Eyelids  extended,  allow  them  to  be  ac- 
curately applied  to  each  other,  and  prevent  them  from  being  col- 
lected into  folds. 

Glandul.e  Sebaceve,  Ciliares,  or  MEIBOMI  ANJE, — 
the  1 all  teim  obtained  from  theii  being  defcribed  by  Meibomi- 
us, — are  placed  between  the  Tat  bus  and  lining  of  the  Eye-lids, 
an. I are  formed  of  a feries  of  white  lines  or  Follicles,  running  in 
fei pentinc  dueflions,  which,  when  viewed  through  a magnifier, 
nnpear  like  rows  otaPearls,  fiom  which  an  Oily  or  Sebaceous 
Matter,  refembling  little  woims,  may  be  readily  fqueezed  out 


25 


through  the  Foramina  or  punfla  Cilaria,  placed  upon  the  edges 
of  the  Eve-lids. 

The  Matter  of  the  Sebaceous  Glands  facilitates  the  motion  of 
the  Eye  lids,  and  prevents  their  accretion  during  fleep. 

Cilia. 

The  Cilia,  or  Eye-lajhes,  are  (tiff  Hairs  placed  in  the  edges  of 
the  Eye-lids.  Thole  of  the  upper  Eye-lid  are  bent  upwards,  and 
are  conliderably  longer  than  thofe  of  the  under  Eye-lid,  which 
are  bent  in  the  oppulite  direff  on.  In  both  Eye-lids,  they  are 
awanting  near  the  inner  Angle. 

The  Cilia  prevent  dull,  infeffs,  &c.  from  getting  into  the 
Eye,  affilt  in  moderating  the  quantity  of  light  fent  into  it,  and 
add  to  the  beauty  of  the  Face. 

Glandula  Lacrymalis. 

The  Glandula  Lacrymalis,  called,  till  of  late  years,  the  Glan- 
dula Innominata  Gai.eni,  is  ficuated  upon  the  upper  and  outer 
part  of  the  Eye,  in  a hollow  behind  the  outer  end  of  the  Superci- 
liary Ridge  of  the  Frontal  Bone.  — [t  is  a Gland  of  the  Conglo- 
merate kind,  of  a yellowifh  colour,  of  an  oblong  form,  and  a 
little  flattened,  with  one  end  pointing  to  'the  Noi'e,  the  other  to 
the  outer  angle  of  the  EVe. 

Befides  this,  there  is  a chain  of  Smaller  Glands,  lying  between: 
thep.incipal  Gland  and  upper  Eye-lid,  and  connecting  them  to- 
gether. 

In  the  direflion  of  the  Smaller  Glands,  there  are  feveral  Ex- 
cretory Duds, — delcribed  by  Dr.  Monro,  1758, — which  run 
nearly  parallel  to,  but  do  not  communicate  with  each  other. 

The  Excretory  Duffs,  on  account  of  their  fmallnefs,  are  not 
often  feen,  and  are  difficult  of  injeffion.  They  terminate  on  the 
inner  fide  of  the  upper  Eye-lid,  near  the  outer  angle  of  the  Eye, 
and  upper  edge  of  theTarfus. 

The  ufe  of  this  gland  is  to  fecrete  the  Tears,  which  are  fpread 
over  the  Surface  of  the  Eye  by  their  own  weight,  and  by  the 
motion  of  the  Eye-lids,  for  the  purpofe  of  preferving  the  delicacy 
of  the  Eye,  and  particularly  the  tranfparency  of  the  Cornea. 

PUNCTA  LACRYMALIA. 

The  Punfia  Lacrymalia  are  two  fmall  Orifices  placed  near  the 
inner  angle  of  the  Eye,  one  in  the  upper,  the  other!  in  the  under 
Eye-lid,  at  the  extremity  of  the  Tarfus,  and  oppoiite  to  each 
other. 

Each  Punflum  is  feated  obliquely  upon  a fmall  eminence,  and 
is  furrounde  l with  a Cartilaginous  Circle,  which  keeps  it  con- 
ftantly  open. 

The  Punfla  Lacrymalia  are  the  Orifices  of  two  fmall  Canals, 
which  run  its  the  direflion  of  the  edges  of  the  Eye-lids  towards 

Vol.  II.  C 


26 

the  fide  of  the  Nofe,  where  they  approach  each  other,  and  termi- 
nate together  in  the  Lacrymal  Sac. 

The  Tears  which  remain  after  moiftening  the  Eye  are  abforbed 
by  the  PunCla,  after  the  manner  of  Capillary  attraction,  and  are 
conveyed  through  their  Duds  into  the  Lacrymal  Sac  by  the  im- 
pulfe  of  the  Eye- lids. 

Cahuncula  Lacrymalis. 

The  Caruncula  Lacrymalis  is  a fmall  Gland  of  a reddifh  colour, 
of  the  Conglomarate  kind,  fituated  between  the  inner  angle  of 
the  Eye-lids  and  Bali  of  the  Eye,  which  fupplies  Sebaceous 
Matter  to  this  part  of  the  Eye-lids,  and  ferves  in  particular  to 
Separate  the  PunCla  Lacrymalia,  and  to  direft  the  Tears  to  them 
while  the  Eye-lids  are  fhut. 

Minute  Hairs  are  found  upon  the  Surface  of  this  body,  ferving 
to  entangle  fmall  objeCls  which  get  into  the  Eye. 

Valvula  Semilunaris. 

The  Valvula  Semilunaris  is  a fmall  doubling  of  the  Tunica 
ConjunCliva,  which  lies  between  the  Caruncula  Lacrymalis  and 
Ball  of  the  Eye. 

It  is  larger  in  the  Ape  and  other  Quadrupeds  than  in  the  Hu- 
man fpecies,  and  (fill  larger  in  Birds,  in  which,  as  well  as  in 
Quadrupeds,  it  is  called  Membrana  NiHitans. 

It  is  in  form  of  a Crefcent,  the  horns  of  which  are  turned  to- 
wards the  PunCla  Lacrymalia,  and  aflifls  the  Caruncula  in  con- 
ducting the  Tears  to  the  PunCla. 

THE  BALL  OF  THE  EYE. 

The  Ball,  Globe,  or  Bulb  of  the  Eye,  is  of  a fphevical  form,  to 
colled  the  rays  of  light  into  a proper  Focus,  and  is  furrounded 
behind  by  a quantity  of  foft  Fat,  to  allow  the  Eye  and  its  Muf- 
cles  to  move  with  facility. 

The  Ballot  the  Eye  is  compofed  of  Coats,  Humours,  Veffels, 
and  Nerves,  to  be  next  defcribed. 

COATS. 

Tunica  Adnata. 

The  Tunica  Adnata,  or  ConjunEliva,  named  from  its  connec- 
ting the  Eye  to  the  Orbit,  is  a reflection  of  the  Skin  continued 
from  the  Eye-lids  over  the  whole  fore-part  of  the  Ball  of  the 
Eye. 

It  adhere B flightly  by  means  of  Cellular  Subftance  to  the 
White  of  the  Eye,  but  fo  firmly  to  the  Cornea,  as  to  be  feparated 
from  it  with  difficulty. 

It  is  fo  remarkably  thin,  that  the  colour  of  the  fubjacent  parts 
fhine  readily  through  it. 

Between  this  Coat  and  the  white  part  of  the  Eye,  there  is  a 
quantity  of  loofe  Cellular  Subftance,  which  is  very  Vafcular, 
and  is  the  common  feat  of  Ophthalmia. 


27 


The  Tunica  Adnata  fup ports  the  Ball  of  the  Eye,  prevents 
extraneous  bodies  from  getting  to  the  back-part  of  it,  and  forms- 
a l'mooth  covering  to  leflen  the  friction  between  the  Eye  and  Eye- 
lids. 

Cornea. 

The  Cornea,  fo  called  from  its  refemblance  to  Horn,  is  termed 
by  many  Authors  Cornea  Lucida,  to  diilinguifh  it  from  the  Scle- 
rotica, named  Cornea  Opaca. 

It  forms  the  anterior  Pellucid  Covering  of  the  Eye,  is  more 
convex  than  the  reft  of  the  Ball,  and  is  joined  to  the  Tunica 
Sclerotica,  like  the  Segment_of  al'mall  Sphere  to  that  of  a lar- 
ger one.  The  convexity,  however,  varies  in  different  perlons, 
Jo  as  to  form  a fliort  or  long  lighted  Eye,  according  as  the  Cor- 
nea is  more  or  lei’s  prominent. 

Ill  a recent  fubjeft,  it  is  hard,  denfe,  and  tranfparent  ; but 
after  maceration  in  water,  it  becomes  loft  and  opaque,  and  may 
be  readily  feparated,  efpecially  in  voting  Animals,  into  differ- 
ent Lamellae,  the  anterior  of  which  is  the  continuation  of  the 
Tunica  Adnata. 

By  a (light  degree  of  putrefaction,  it  may  alfo  be  feparated 
from  the  Tunica  Sclerotica. 

In  the  Whale,  the  edge  of  the  Cornea  is  received  into  a diftinCl 
Groove-formed  by  the  Sclerotica. 

In  a found  ftate,  it  has  no  Veflels  which  carry  red  Blood, 
though  fucli  are  frequently  feen  on  it  when  the  Eye  is  inflamed. 

Its  nerves  are  too  frnall  to  be  traced;  yet  it  poffefl'es  exquifite 
fenfibility. 

It  collects  the  rays  of  light,  and  tranfmits  them  to  the  Eye, 
protects  the  tender  parts  within  it,  and  contains  the  Aqueous 
Humour. 

Iris. 

The  Iris,  which  is  named  from  being  in  fome  perfons  of  dif- 
ferent colours,  is  the  only  Coat  which  poffefl'es  motion.  It  was 
conlidered  as  a continuation  of  the  Choroid  Coat,  until  defcribed 
by  Zinn,  who  (hews  that  it  is  only  connected  to  this  Coat  byt- 
the  medium  of  the  Ciliary  Circle. 

It  is  placed  at  a little  diftance  from  the  Cornea,  begins  a f ilia'll 
way  behind  the  j unCtion  of  that  Coat  with  the  Sclerotica,  and 
running  acrofs,  it  forms  a Septum,  a little  convex  anteriorly, 
and  perforated  in  the  middle  by  a Hole,  called  the  Pupil,  or 
fight  of  the  Eye. 

The  term  Pupil  is  applied,  becaufe  it  reprefents  objeCts  no  lar- 
ger than  a Papilla  or  Puppet. 

In  the  Foetus,  the  Pupil  is  cove:  ed  with  a Vafcnlar  Membrane, 
termed  Membrana  Pupillaris,  which  generally  dil’appears  between 
the  feventh  and  ninth  month  of  geftation. 


28 


Upon  the  back-part  of  the  Iris,  there  is  a dark-coloured  Pig- 
ment, confidered  by  the  Ancients  as  a pofferior  Layer  of  the 
Iris,  called  by  them  Uvea,  from  its  refemblance  in  colour  to 
the  Grape. 

When  the  Paint  is  wafiied  off,  the  Iiis  exhibits  two  fets  of 
Fibres,— concerning  which  Authors  have  entertained  various 
opinions, — one  in  the  form  of  Radii,  the  different  colours  of 
which  give  the  diverfity  of  colour  to  the  Eye  ; the  other  circular, 
and  furrounding  the  inner  edge  of  the  Iris,  an'd  confidered  by,  « 
Dr.  Monro  as  the  Sphinfter  Mufcle  of  the  Pupil. 

The  Iris  has  alfo  many  Blood-vtffels,  which  can  be  readily 
injefled  ; and  has  a greater  proportion  of  Nerves  than  almoft  any 
other  part  of  the  Body. 

It  floats  in  the  Aqu-tous  Humour,  and  is  of  fuch  a nature, 
that  upon  expolure  to  a ftrong  light,  or  when  the  Eye  looks  upon 
a near  objeft,  the  diameter  of  the  Pupil  is  diminifhed;  and  vice 
verfa. 

The  different  motions  of  the  Iris  are  fuppofed  to  be  excited  by 
the  fenfibility  of  the  Retina,  and  the  quantity  of  light  falling 
upon  that  Nerve. 

The  Iris  ferves  to  regulate  the  quantity  of  light  fent  to  the 
bottom  of  the  Eye. 

Tunica  Sclerotica. 

The  Tunica  Sclerotica,  which  is  named  from  its  hardnefs,  is 
the  largeft  and  ftrongeff  Coat  of  the  Eye,  covering  the  whole 
Ball,  excepting  the  parts  occupied  by  the  entrance  of  the  Optic 
Nerve  behind,  and  by  the  Cornea  before. 

It  is  fo  firmly  fixed  to  the  edge  of  the  Cornea,  as  to  have  been 
confidered  by  many  Anatomills  as  a continuation  of  the  fame 
fubitance;  but  it  differs  from  the  Cornea  in  the  following  parti- 
culars ; it  is  of  a pure  white  colour,  is  formed  of  Fibres  running 
in  every  direction,  and  clofely  interwoven  with  each  other,  is 
not  divifible  into  Layers,  and  may  be  fepafated  from  it  by  art, 
as  has  been  already  mentioned. 

It  is  thickeit  pofter'orly,  and  receives  a little  tinge  on  the 
inner  Surface,  from  the  Choroid  Coat,  with  which  it  is  in  con- 
ta£l. 

It  gives  form  and  ftrength  to  the  Eye,  and  fupports  the  tender  ' 
parts  within  it. 

The  Tendons  of  the  four  Recli  Mufcles  of  the  Eye  are  fixed 
to  the  fore-part  ot  the  Tunica  Sclerotica  ; and  thefe,  or  the  Cel- 
lular Vaginae  covering  them,  have  been  fuppofed  to  give  an  ad- 
d tional  whitenefs  to  the  Eye  ; and  the  part  giving  this  whitenefs 
lias  been  termed  Tunica  Albuginea  But  the  Sclerotic  Coat  is 
every  where  of  a pure  white,  and  can  receive  little  additional 
brighmefs  from  any  fuch  coverings. 


29 


Tunica  Choroides. 

This  Coat  derives  its  name  from  the  Veffels  with  which  it 
abounds,  forming  a Chorus ; or  from  its  fuppofed  refemb lance 
to  the  Membrane  called  Chorion , which  furrounds  the  Fcctus  in 
Utero. 

The  Choroides  lies  under  the  Sclerotica,  and  is  connected  to  it 
by  the  Trunks  of  Veffels  and  Nerves  which  pals  from  the  one 
Coat  to  the  other,  and  all’o  by  a tender  Cellular  Subftance,  or  a 
brown  colour,  with  which  the  inner  Surface  of  the  Sclerotica  is 
tinged. 

It  begins  at  the  entrance  of  the  Optic  Nerve  into  the  Eye,  runs 
between  the  Sclerotica  and  Retina,  nearly  to  the  Cry ftal line 
Lens,  where  it  is  more  firmly  connefted  to  the  bclerotic  Coat 
than  it  is  elfewiiere,  by  means  of  the  Ciliary  Circle. 

The  Ciliary  Circle,  or  Ciliary  Ligament  it  is  called,  is  com- 
posed of  a quantity  of  condenfed  filming  Cellular  Subftance,  which 
forms  a white  Ring  connecting  the  fore-part  of  the  Choroides, 
and  the  root  or  outer  Margin. of  the  Iris,  to  the  Sclerotica. 

The  Choroid  Coat  is  much  thinner  and  more  tender  than  the 
Sclerotic,  and  is  one  of  the  moft  Vafcuiar  parts  of  the  Body, 
leeming  at  firft  fight  to  be  entirely  compofed  of  Veffels. — The 
greater  number  of  thofe  on  the  outiide  run  in  whirls  ; while  thole 
on  the  inlide,  running  nearly  parallel  to  each  other,  gave  rife  to 
the  fuppoled  exiltence  of  the  Membraua  Ruyfchiana. 

It  is  alfo  furnilhed  with  numerous  Nerves,  which  are  united 
with  its  Veffels  by  a fine  Cellular  Texture. 

In  the  human  Eye,  the  Choroides  is  of  a dufky  brown  colour, 
both  externally  and  internally  ; out  the  colour  varies  confideva- 
biy  in  the  eyes  of  different  animals- 

The  inner  Surface  of  this  Coat,  which  is  Villous,  was  defcrib- 
ed  byRuyscH  as  a diflinSi  Lamina,  and  has  been  termed  by 
many  Anatomifts  Tunica  Ruyfchiana  ; — Haller  however,  and 
Zinn,  and  many  others  who  followed  them,  have  demonftrated 
this  Coat  to.  conlift  of  only  one  Lamina  ; though  in  Sheep, 
and  n l'orue  other  animals,  it  appears  to  be  double. 

Upon  the  inner  tide  of  the  Choroides,  there  is  a dark-coloured 
Mucus,  called  Pig/nentum  Nigrum , — fuppofed  to  be  produ  ed 
from  the  Veffels  of  this  Coat, — which  is  blackeft  and  t'nickeft  at 
the  fore  part  of  the  Eye,  where  it  adheres  l'o  tenacioufly  as  io  be 
removed  with  difficulty  ; bur  behind  it  is  thinner,  more  fluid, 
and  more  eaiily  removed;  becoming  gradually  lefs  evident,  and 
almolt  difappearing  round  the  Optic  Nerve. 

In  advanced  age,  the  Pigmentum  Nigrum  becomes  more  di- 
luted, and  of  a lighter  colour  ; lb  that  the  Veffels  of  the  Cho- 
roid Cuat  may  be  l'een  fhining  through  the  Vitier.us  H • • 

You  II.  C 2 h ' 


30 

Though  Haller,  denies  that  the  Membrana  Ruyfchiana  can 
ever  be  leparated,  in  the  Human  Eye,  fiom  the  Choroides,— he 
retains  the  name,  to  denote  the  black  Surface  of  this  Coat. 

In  grameniverous  animals,  in  fifhes,  and  in  thofe  animals 
which  go  in  quell  of  prey  in  the  night,  the  Paint  is  of  a light  and 
/hining  colour  in  the  bottom  of  the  Eye,  and  is  called  Tapetum. — 
In  an  entirely  white  Rabbit,  the  Paint  is  awanting,  and  the  Eye 
has  a red  colour  from  the  Velfels  of  the  Choroid  Coat  ; but  the 
rednefs  difappears  when  the  animal  is  dead. 

At  the  fore-part  of  the  Choroid  Coat,  and  oppofite  to  the  Cili- 
ary Circle,  there  is  a black  radiated  Ring,  called  Corpus  Ciliare, 
which  is  about  the  fixth  part  of  an  inch  in  breadth  towards  the 
Temple,  but  fomewhat  narrower  towards  the  Nofe. 

In  the  pofterior  portion  of  the  Corpus  Ciliare,  there  are  nu- 
merous pale  radiated  Ciliary  Stria,  but  fo  covered  with  the  Pig- 
menium  Nigrum,  as  not  to  be  diftinftly  feen  till  the  Paint  is  re- 
moved. 

Near  the  connection  of  the  Corpus  Ciliare  with  the  root  of  the 
Iris,  t'nefe  Striae  become  gradually  broader  and  more  elevated,  and 
form  about  feventy  white  Plica  or  Folds,  termed  ProceJJus  Ciliares, 
the  intervals  of  which  are  alfo  covered  with  Pigmentum  Ni- 
grum. 

The  ProceJJus  Ciliares,  which  obtain  their  name  from  their  re- 
femblance  to  the  Cilia  of  the  Eye-lids,  are  commonly  formed  each 
of  two  or  more  Striae,  are  not  all  of  an  equal  fize,  and  many  of 
them  forked  at  their  extremities. 

The  Corpus  Ciliare,  formed  of  the  Ciliary  Strias  and  Ciliary 
Procefies,  has  no  appearance  of  Mufcularity,  though  the  contrary 
has  been  fuppofed  by  fome  Authors.  A fine  Injection  (hew;  it 
to  be  chiefly  formed  of  a continuation  of  the  Blood-veflels  of  the 
Choroid  coat,  the  branches  of  which  divideinto  fuch  minute  parts, 
■as  to  give  the  whole  a Viilous  appearance. 

The  Corpus  Ciliare  is  glued  to  the  Retina,  at  the  fore-part  of 
the  Vitreous  Humour,  .aiid  a little  behind  the  edge  of  the  Cry- 
ftalline  Lens  ; but  the  Ciliary  Procefies  float  in  the  Aqueous  Hu- 
mour in  the  pofterior  chamber  of  the  Eye,  at  tile  inner  fide  of  the 
root  of  the  Iris,  and  may  be  readily  turned  back  behind  the  edge 
of  the  Lens,  to  which  they  are  contiguous,  but  do  not  adhere. 

The  Choroid  Coat,  with  its  dark  Paint,  ferves  to  fuffocate  the 
rays  of  light  which  pals  through  the  Retina,  and  thereby  to  al- 
low a diftm£t  image  to  be  formed  upon  the  bottom  of  the  Eye,  and 
to  prevent  the  rays  from  being  refle&ed  fo  as  to  form  a fecond 
image. 

In  thefe  animals  in  which  this  Coat  or  its  Paint  is  of  a bright 
colour,  it  a6ls  as  a mirror  to  refleft  light,  and  make  the  impreflion 
ftronger. 


31 


Optic  Nerve  and  Retina, 

The  Optic  Nerve,  in  its  pafiage  through  the  Orbit,  is  cover- 
ed by  a continuation  of"  the  Membranes  which  furround  the 
Brain. 

At  the  Foramen  Opticum,  the  Dura  Mater  is  divided  into 
two  Lamina ?,  one  of  which  affifts  in  forming  the  Periofteum  of 
the  Orbit;  the  other,  which  is  again  divided  into  two  Laminae, 
furnifhes  a Iheath  to  the  Nerve,  and  accompanies  it  to  the  Tuni- 
ca Sclerotica,  to  which  it  is  fo  firmly  connected  by  Cellular  Sub- 
ftance,  as  to  have  induced  fome  Authors  to  defcribe  the  Sclero- 
tica as  a continuation  of  the  Dura  Mater. 

The  Body  of  the  Nerve  is  ftill  more  clofely  inverted  by  the 
Pia  Mater,  which  alfo  forms  (heaths  round  the  Nervous  Fafci- 
culi,  and  accompanies  the  Nerve  into  the  Eye. 

At  the  back-part  of  the  Ball  of  the  Eye,  and  a little  removed 
from  the  Axis,  towards  the  Nol'e,  the  Fafciculi  of  the  Optic 
Nerve  pals  through  a Cribriform  part  of  the  Sclerotic  Coat. 

The  Nerve  is  contracted  at  its  entrance  through  the  Sclerotic 
Coat,  but  immediately  after  its  ingrefs,  it  expands  to  form  the 
Retina, — fo  called  from  its  fuppofed  Reticular  appearance. 

In  the  middle  of  the  entrance  of  the  Optic  Nerve,  the  Artery 
is  l'een  dividing  into  branches,  which  are  difperfed  upon  the  in- 
ner Surface  of  the  Retina. 

The  Retina  advances  between  the  Choroid  Coat  and  Capfule 
of  the  Vitreous  Humour,  to  the  fore-part  of  the  Eye,  and  ter- 
minates ordifappears  upon  the  anterior  part  of  the  edge,  or  great- 
ell  diameter  of  the  Capfule  of  the  Cryrtalline  Lens. 

The  Retina  is  contiguous  to  the  Choroid  Coat  and  Capfule  of 
the  Vitreous  Humour,  but  does  not  adhere  to  either,  by  Blood- 
vSfiels  or  otherwife,  till  it  reach  the  Corpus  Ciliare. 

Under  the  Corpus  Ciliare,  the  Retina  is  fo  covered  externally, 
with  the  Pigmentum  Nigrum,  and  adheres  internally  fo  clofely 
to  the  Capfule  of  the  Vitreous  Humour,  as  to  be  prevented  from 
being  l'een  till  the  black  Paint  be  waflied  off,  or  till  all  the  Coats 
be  removed  pofteriorly,  and  the  Eye  viewed  through  the  medium 
of  the  Vitreous  Humour. 

The  Retina  is  compoled  of  a tender  and  Pulpy-like  Subftance, 
is  femi-tranfparent,  and  of  a light-grey  colour,  refembling  that 
of  gi ound  glafs. 

From  the  entrance  of  the  Optic  Nerve,  to  the  edge  of  the  Cor- 
pus Ciliare,  the  Retina  is  of  an  equal  and  uniform  Subrtance, 
and  is  foeafily  torn  and  feparated  from  the  edge  of  that  body,  as 
to  be  defcribed  by  many  Authors  as  terminating  there. 

_ Under  the  Striae  and  Procertes  of  the  Corpus  Ciliare,  the  Re- 
tina is  thinner  than  in  the  pofterior  part  of  the  Eye,  and  is  fo  im- 


32 


preffed  by  thefe  bodies,  as  alfo  to  have  the  appearance  of  Str'x, 
which  terminate  in  numerous  minute  Fibres,  like  Nerves  in 
other  parts  ol  the  Body. 

The  Retina  is  the  feat  of  Vifion,  and  therefore  the  primary 
part  of  the  Eye,  to  which  all  the  other  parts  within  the  Orbit  are 
l'ubfervient. 

HUMOURS. 

Aqueous  Humour. 

The  Aqueous  Humour  is  lodged  in  the  fpace  between  the  Cor- 
nea and  Cryftalline  Lens. 

This  fpace  is  divided  into  two  Cavities,  called  Chambers,  the 
anterior  of  which  is  fituated  between  the  Cornea  and  Iris,  and  is 
the  larger  of  the  two. 

The  pofterior  is  placed  between  the  Iris  and  Cryftalline  Lens, 
and  is  fo  much  fmaller  than  the  former,  that  its  exiftence  has 
been  denied  by  fome  Authors,  though  it  is  a diftin<5l  Cavity,  de- 
monftrable,  not  only  in  the  Adult,  where  the  Pupil  is  open,  but 
in  the  Foetus  before  the  Pupil  is  formed. 

The  Aqueous  Humour  is  clear  as  the  pureft  Water,  but  is 
fomewhat  heavier,  poflefles  a fmall  degree  of  vifcidity,  contains 
a little  Salt,  and  is  about  five  grains  in  weight. 

In  the  Foetus,  and  for  the  firft  month  after  birth,  it  is  reddifh 
and  turbid. 

When  evacuated,  it  is  quickly  renewed  ; for  within  forty- 
eight  hours  after  it  has  been  let  out  by  a punflure,  the  Cornea  is 
obferved  to  be  again  perfectly  diftended. 

It  is  fuppofed  to  be  fecreted  from  the  neighbouring  Arteries, 
particularly  from  thofe  on  the  fore-part  of  the  Iris  and  Ciliary 
Proceftes. 

It  lerves  to  keep  the  Cornea  diftended,  and,  by  its  roundifh 
form  and  pell ucidity,  it  colledls  and  tranfmits  the  rays  of  light 
to  the  inner  parts  of  the  Eye.  It  likewife  guards  the  Iris  and 
Lens,  and  admits  of  the  motions  of  the  former. 

Crystalline  Lens. 

The  Cryjfallbie  Lens,  which  has  its  name  from  its  refemblance 
to  Cryftal,  and  from  its  Lenticular  form, — though  a folid  body, 
which  may  be  moulded  into  various  fhapes, — has  always  been 
claflVd  among  the  Humours  of  the  Eye. 

It  is  fituated  behind  the  Aqueous  Humour,  oppofite  to  the 
Pupil,  and  the  whole  of  its  pofterior  part  is  received  into  a de- 
preflion  on  the  fore-part  of  the  Vbreous  Humour. 

L ke  a common  Lens,  or  magnifying  Glafs,  it  has  two  convex 
Surfaces,  the  anterior  of  which  is  in  general  lefs  convex  than  the 
pofterior,  the  two  being  formed  of  fegments  of  fpheres  of  an  un- 
equal fize. 


OJ 


The  anterior  Surface,  according  to  the  experiments  of  Petit, 
forms  the  fegment  of  a fphere,  the  diameter  of  which  is  between 
feven  or  eight  lines,  or  twelfths  of  an  inch;  while  the  pofterior 
Surface  is  only  equal  to  the  fegment  of  a fphere  of  about  five  lines 
in  diameter. 

It  has  been  obferved  by  Zinn, — that  the  figure  of  the  Lens 
varies  at  different  periods,  being  in  the  Foetus  almotl  of  a Ipheri- 
cal  form,  but  becoming  gradually  flatter  on  the  anterior  and  pof- 
terior Surfaces,  till  about  the  age  of  thirty,  after  which  its  form 
does  not  appear  to  vary. 

As  the  figure,  fo  alfo  the  colour  and  confiftency  are  found  to 
change  at  different  times  of  life.— In  the  Foetus,  not  only  the 
Capfule,  but  the  Lens  alfo  is  of  a reddifh  colour  ; but,  imme- 
diately after  birth,  they  become  perfeffly  tranfparent. — In  a per- 
fon  confiderably  advanced  in  years,'  the  Lens  is  obferved  to  ac- 
quire a certain  degree  of  yellownefs,  which  appears  fii  If  in  the 
centre,  and  afterwards  extends  gradually  to  the  circumference  ; 
and  in  extreme  old  age,  this  yellow  tinge  becomes  lo  deep  as  to 
referable  Amber. 

An  Aqueous  Fluid  is  deferibed  as  being  fituated  between  the 
Cryftalline  Lamellae,  which  is  fuppofed  to  decreafe  in  quantity, 
and  to  become  yellowiflr,  the  Lens  at  the  fame  time  increafing  in 
folidity  as  the  perfon  advances  in  life. — This  difference  however, 
of  convexity,  colour,  and  confidence,  according  to  the  difference 
of  age,  is  not  uniformly  met  with. 

The  Lens  becomes  opaque  foon  after  death,  and  acquires  a a 
additional  opacity  when  put  into  fpirit  of  wine. 

It  is  compofed  of  concentric  Lamellae,  laid  over  each  other 
like  the  coats  of  an  Onion.  Thele  Lamellae  are  connefiled  by  a 
fine  Cellular  Subftance,  and  are  more  clofely  compacted  the  near- 
er they  are  to  the  centre.  ‘ 

This  lamellated  ftru&ure  may  be'  readily  obferved  in  the  Eye 
of  an  Ox,  or  any  other  large  animal,  but  is  moft  evident  when  the 
Lens  has  been  macerated  in  Water  or  Vinegar. 

When  the  maceration  is  continued  for  fome  time,  the  Lamel- 
lae put  on  a radiated  appearance,  the  Radii  running  in  a vertical 
manner,  or  iffuing  from  the  centre  to  the  circumference,  dividing 
the  Surface  into  Ifofcular  Triangles. 

The  Lamellae  were  difeovered  by  Leuwenhoeck,  to  be  of  a 
Fibrous  ftrufture.  By  a late  writer,  thefe  Fibres  have  been  con- 
fidered  as  Mufcular, — but  this  opinion  of  the  Mufcularity  of  the 
Lens,  feems  to  have  gained  very  few  profelytes. 

The  fubftance  of  the  Lens  fomewhat  refembles  half-melted 
Gum,  is  very  foft  and  tender  on  the  outfide,  but  becomes  gra- 
dually firmer  and  tougher  towards  the  centre,  where  it  forms  3 
N ucleus . 

The  Lens  is  furrounded  by  a very  pellucid  proper  Capfule, 
called  Tunica  Aranea,  or  CrjJiallina,  which  is  much  thicker  and 


34 


more  elaftic  tlian  the  Capfule  of  the  Vitreous  Humour,  but  ad- 
heres fo  flightly,  and  is  fo  eafily  lacerated,  that  after  a fmall 
punfture  is  made  in  it,  the  Lens  ftarts  out,  upon  applying  gen- 
tle prefiTure  to  the  Capfule. 

The  pofterior  part  of  the  Capfule  is  much  thinner,  fofter,  and 
■weaker  than  the  anterior  ; but  is  quite  a diJUnfl  Membrane  from 
the  Tunica  Vitrea  ; yet  fo  firmly  connected  to  it  by  Cellular  Sub- 
fiance,  that  it  is  difficult  to  feparate  them  without  lacerating  both 
the  Vitreous  Coat  and  its  Humour. 

Some  Authors  defcribe  an  Aqueous  Humour  as  feated  between 
the  Lens  and  its  Capfule;  while  others,  of  no  fmall  refpeflabili- 
ty,  deny  the  exiftence  of  this  Humour,  as  well  as  of  that  which 
is  faid  to  be  tituated  between  the  Lamella?  of  the  Lens. 

The  VeJJ'els  of  the  Lens  are  not  to  be  feen  in  the  Eye  of  an 
Adult  ; but  in  that  of  a Foetus,  Petit  found  Vefl'els  palling 
from  the  Corpus  Ciliare,  over  the  fore-part  of  the  Capfule  of  the 
Lens. 

Winslow  afterwards  obferved,  that  in  the  Foetus,  and  in  new- 
born children,  a fine  injeftion  fucceeded  fo  well  as  to  difcover  the: 
Vef.'els  of  the  Membrana  Cryftalina  and  Vitrea  ; — and  in  a Foe- 
tus of  about  fix  months,  the  injected  liquor  feemed  to  him  to  have 
penetrated  a part  of  the  Cryftalline  and  Vitreous  Humours. 

Albinus  derives  thefe  veffels  from  a double  fource.— In  the 
Eye  of  a Whale,  he  demonftrated  Veffels  palling  from  the  Cilia- 
ry Procefi'es  to  the  Subftance  of  the  Lens  ; — and,  at  a later  peri- 
od, he  injetted  in  the  human  Eye,  a fmall  bianch  arifing  from 
the  Central  Artery  of  the  Retina,  which  proceeded  in  a ftraight 
direction  through  the  Vitreous  Humour,  and  divided  in  the  pofte- 
riorpart  of  the  Capfule  into  numerous  branches,  many  twigs  of 
which  plunged  into  the  Subftance  of  the  Lens. 

This  artery  and  its  branches  have  been  frequently  and  fuccefs- 
fully  injefied  by  fucceeding  Anatomifts. 

Vitreous  Humour. 

The  Vitreous  Humour,  fo  called  from  its  refemblance  to  melted 
Glafs,  is  fituated  in  the  back-part  of  the  Cavity  of  the  Eye,  which 
it  occupies  from  the  infection  of  the  Optic  Nerve  to  the  Surface  of 
the  Cryftaline  Lens. 

It  is  round  at  the  back-part  and  fides,  where  it  is  covered  by 
the  Retina,  but  is  concave  before,  where  it  forms  a bed  for  the. 
Cryftalline  Lens. 

It  is  by  much  the  largeft  of  the  three  Humours,  occupying 
upwards  of  nine-tenths  of  the  whole  Eye,  and  has  a Gelatinous 
appearance, — or  is  fomewhat  like  the  glaire  of  an  Egg. 

In  an  Adult  it  is  always  very  tranl'parent,  and  in  an  Old  Per- 
fon  it  does  not  like  the  Lens,  degenerate  into  a yellow,  or  any 
other  colour. 


oo 


In  the  Fcetus,  like  the  Aqueous  Humour,  it  is  of  a reddifh 
colour. 

The  liquor  with  which  the  Vitreous  Humour,  is  filled,  is 
fimilar  to  the  Aqueous, — very  fluid,  tranfpires  readily  through 
theCapfule,  thou/h  that  Coat  be  entire,  and,  like  the  Aqueous 
Humour,  is  fomewhat  thicker,  heavier,  and  more  vifcid  than 
Water. 

When  this  Humour  is  evacuated  by  punffure,  in  the  living  Bo- 
dy, it  is  very  feldom,  though  fometimes  renewed. 

Upon  the  Surface  of  this  Humour  there  is  a Coat,  termed  Vi- 
trea,  as  tranfparent  as  the  Humour  itfelf,  and  fo  thin  and  Cob- 
web-like,  as  to  have  the  name  of  Aranea. 

The  Tunica  Vitrea  is  remarkably  fmooth  on  its  outer  Surface; 
but  within  it  fends  Procefies  into  the  body  of  the  Humour. 

Some  Authors,  and  among  thefe  Winslow,  have  defcribed 
this  Coat  as  confiding  of  two  Laminae,  but  Sabatier,  and 
other  late  writers,  feem  fufficiently  fatisfied  that  it  is  a Angle 
Layer ; and  even  this  fingle  Layer  cannot  be  railed  but  with  dif- 
ficulty, though  it  is  demonftrable  by  making  a punfture  to  allow 
the  Humour  to  efcape,  and  by  afterwards  dillending  the  part  with 
air. 

The  ftrufture  of  the  humour  confifts  in  a fet  of  delicate  Cells, 
which  contain  the  liquor  within  them,  as  may  be  feen  by  the 
afliflance  of  Acids,  or  by  boiling  Water,  or  by  Congelation. 

The  Cells  of  the  Humour  communicate  freely  with  each  other, 
as  appears  from  the  liquor  oozing  out  by  the  fmallefl:  pundlure 
made  in  the  general  Capfule. 

Under  the  Corpus  Ciliare,  the  Capfule  of  the  Vitreous  Hu- 
mour fends  off  an  external  Lamina,  which  accompanies  the  Re- 
tina, and  is  inferted  with  it  into  the  fore-part  of  the  Capfule  of 
the  Lens,  a little  before  its  anterior  edge.  It  is  termed  Mem- 
branula  Corona:  Ciliaris,  or  Zomula  Ciliaris,  from  its  Striated 
appearance  and  Circular  form,  and  aflifts  in  fixing  the  Lens  to 
the  Vitreous  humour. 

After  fending  off  the  Ciliary  Zone,  the  Coat  of  the  Vitreous 
Humour  goes  behind  the  Capfule  of  the  Lens,  to  which  it  firmly 
adheres. 

Between  the  Ciliary  Zone  and  part  where  the  Capfule  of  the 
Vitreous  Humour  adheres  to  that  of  the  Lens, — which  is  at  the 
fame  diftance  behind  the  edge  of  the  Lens  with  the  diftance  of  the 
infection  of  the  Ciliary  Zone  before  it, — a Paflage  is  formed,  na- 
med Canalis  P etitianus , after  Petit,  who  difcovered  it. 

The  Membranes  forming  this  Paflage  are  pervaded  by  tranf- 
verfe  Fibres,  in  fuch  a manner,  that  when  air  is  introduced,  it 
goes  freely  round  the  edge  of  the  Lens;  but  the  Paflage  has  a 
Cellular  appearance,  being  contra&ed  and  dilated  alternately. 


36 


The  Canal  of  Petit  is  nearly  of  the  fame  breadth  with  the 
Corpus  Ciliare,  is  always  empty  and  has  no  communication  with 
the  Capfules  of  the  Vitreous  or  Cryftalline  Humours. 

Nu  Vefiels  are  to  be  feen  in  the  Vitreous  Humour  of  an  Adult, 
but  in  the  Eye  of  a Foetus,  an  artery  is  ol-ferved  to  arife  from 
the  central  one  of  the  Retina,  which  pafl'es  through  the  middle  of 
the  Vitreous  Humour,  fending  twigs  to  the  Cellular  Texture  of 
this  Humour  while  the  principal  Trunk  is  continued  to  the  Cap- 
fule  of  the  Cryftalline  Lens,  as  has  been  aheady  obferved. 

The  Vitreous  Humour  ferves  to  give  fhape  to  the  Eye,  to  keep 
the  Coats  properly  expanded,  to  preferve  the  due  diftance  of  the 
Lens,  and  direff  the  rays  of  light  to  the  Retina. 

MUSCLES  OF  THE  BALL  OF  THE  EYE. 

The  Ball  of  the  Eye  is  moved  by  fix  Mufcles,  which  are  divi- 
ded, on  account  of  their  d'reftion,  into  Jour  Jlraight  and  tnxio 
oblique  Mufcles,  obtaining  their  refpective  names  from  their  fize, 
fituation,  dire&ion,  or  ufe. 

Of  the  ftiaight  Mufcles,  one  is  fituated  above  the  Eye,  ano- 
ther below  it,  and  one  on  each  fide.  Of  the  oblique,  one  is  placed 
at  the  upper  and  inner,  and  the  other  at  the  under  and  cuter  part 
of  the  Eye. 

The  Rebli  Mufcles  are  not  ftraight,  as  the  name  implies  ; for, 
on  account  of  the  fituation  of  the  Eye  and  fhape  of  the  Orbit,  the 
internal,  or  that  next  the  Nofe,  is  the  only  one  which  funs  in  a 
ftraight  direflion. 

Neither  are  they  all  equally  long,  the  internal  being  the  fliort- 
eft,  the  external  the  longeft,  and  the  other  two  nearly  of  the  fame 
length. 

The  four  ftraight  Mufcles,  which  bear  a ftrong  refemblance  to 
each  oilier,  arife  by  a narrow  beginning,  a little  Tendinous  and 
Flefhy,  from  the  edge  of  the  Foramen  Opticum,  where  they  em- 
brace the  Optic  Neive  at  its  entrance  into  the  Orbit. 

In  their  palfage  foi  wtirds,  they  form  Flefhy  Bellies,  which 
fend  off  broad  and  very  thin  Tendons,  to  be  inferted  into  the 
Sclerotic  Coat,  under  the  Tunica  Adnata,  about  a quarter  of  an 
inch  behind  the  edge  of  the  Cornea,  and  at  equal  diftances  from 
each  other. 

At  the  place  of  their  infertion  they  arc  fo  intimately  connefted 
wilh  the  Sclerotica,  that  they  cannot  be  feparated  from  it,  or  be 
brought  as  far  as  the  Cornea,  without  evident  laceration. 

The  different  Mufcles  of  the  Ball,  of  the  Eye,  where  they  lie 
upon  the  Ball,  are  covered  with  a Cellular  Sheath,  which  after- 
wards degenerates  into  that  Cellular  Subftance  which  is  interpo- 
fed  between  the  Sclerotica  and  Conjun&iva. 


37 


Levator  Oculi  ; 

Or  ReBus  Attollens,  or  Superbus. 

Origin  : From  the  upper  part  of  the  Foramen  Opticum,  below 
the  Levator  Palpebrae  Superioris. 

Infertion:  Into  the  upper  and  fore-part  of  the  Tunica  Sclero- 
tica. 

Afiion  ; To  raife  the  fore-part  of  the  Ball  of  the  Eye. 

Depressor  Oculi  ; 

Or  Refills  Deprimens,  or  Humilis. 

Origin  : From  the  inferior  part  of  the  Foramen  Opticum. 

Infertion  : Opp*fite  to  the  former. 

Afiion  : To  pull  the  fore-part  of  the  Eye  downwards.  . 

Adductor  Oculi; 

Or  Refius  Adducens,  or  Bibhorius. 

Origin : From  the  Foramen  Opticum,  between  the  Obliquus 
Superior  and  Depreffor. 

Infertion  : Oppoiite  to  the  inner  angle. 

Afiion:  To  turn  the  fore-part  of  the  Eye  towards  theNofc. 

Abductor  Oculi; 

Or  Refius  Abducens,  or  Indignabundus . 

Origin  : From  the  Bony  Partition  between  the  Foramen  Opti- 
cum and  Lacerum. 

Infertion:  Into  the  Ball  of  the  Eye,  oppoiite  to  the  outer 
Angle. 

Afiion  : To  turn  the  fore-part  of  the  Eye  towards  the  Temple. 

When  two  of  the  oppoiite  Refli  Mufcles,  or  all  of  them  aft 
together,  they  draw  the  Eye  into  the  Orbit. 

When  two  of  the  adjacent  Refti  Mufcles  aft,  they  turn  the 
fore-part  of  the  Eye  obliquely  in  a direftion  towards  their  Ori- 
gins. 

Obliquus  Superior; 

Or  Obliquus  Major,  or  Trochlearis. 

Origin  : Like  the  ftraight  Mufcles,  from  the  edge  of  the  Fo- 
ramen Opticum,  between  the  Levator  and  Adductor  Ocuii. 
From  thence  it  runs  ftraight  forward,  fends  off  a long  round  Ten- 
don, which  paftes  through  a Cartilaginous  Pulley  fixed  behind 
the  Internal  Angular  Procefs  of  the  Os  Frontis:  from  this  it 
runs  a little  downwards,  and  returns  backwards  and  outwards, 
palling  under  the  Levator  Oculi,  to  have  its 

Inj'ertion  : By  a Broad  thin  Tendon,  into  the  Tunica  Sclerotica, 
about  half-way  between  the  infertion  of  the  Levator  Oculi  and 
entrance  of  the  Optic  Nerve. 

Afiion:  To  roll  the  Ball  of  the  Eye,  by  turning  the  Pupil 
downwards  and  outvvards. 

Vol.  II.  D 


58 


Obliquus  Inferior.; 

Or  Obliquus  Minor. 

Origin:  By  a narrow  beginning,  from  the  anterior  edge  of  the 
Orbitary  Procefs  of  the  Superior  Maxillary  Bone,  near  the  La- 
crymal  Groove,  from  which  it  palfes  obliquely  outwards,  back- 
wards and  itpwaids,  round  the  Ball  of  the  Eye. 

lnfertion  : By  a broad  thin  Tendon,  into  the  Sclerotic  Coat, 
between  the  entrance  of  the  Optic  Nerve  and  infertion  of  the  Ab- 
duftor  Oculi,  and  oppofite  to  the  intention  of  the  Superior  Ob- 
lique Mufcle. 

ABion  : To  roll  the  Ball  of  the  Eye,  by  turning  the  Pupil  up- 
wards, and  inwards,  and,  with  the  afliftatice  of  the  Superior 
Oblique  Mufcle,  to  pull  the  Eye  forwards,  thereby  becoming  an 
antagonift  to  the  Refti  Mul’cks. 

The  two  Oblique  Mul'cles,  on  account  of  rolling  the  Eye,  and 

(ling  it  in  the  exorelfion  of  certain  paffions,  have  been  called 
Rotatores,  or  Amatores. 

VESSELS  OF  THE  EYE. 

The  Frontal,  Fafcial,  and  Temporal  Arteries,  which  are 
branches  of  the  External  and  Internal  Carotids,  fupply  the  Pal- 
pebrae,  and  communicate  with  tiiofe  which  are  difperfed  within 
the  Orbit. 

Some  final!  branches  of  the  Internal  Maxillary  Artery  pafs 
through  the  Inferior  Orbitar  Filfure,  to  be  difperfed  chiefly  upon 
the  Periofteum  of  the  Orbit  and  Fat  of  the  Eye. 

The  Ocular  Artery,  which  is  a branch  of  the  Internal  Carotid, 
partes  though  the  Foramen  Opticum,  in  company  with  the  Optic 
Nerve,  and  fupplies  the  Fat,  Mufcles,  and  Ball  of  the  Eye,  and 
aifo  the  Lacrytnal  Gland  and  Tunics  Conjunctiva. 

The  brandies  which  belong  to  the  Ball  of  the  Eye,  have  the 
name  ol  Ciliares  : — They  perforate  the  Sclerotica  in  different 
places,  and  are  afterwards  difperfed  chiefly  upon  the  Choroid  Coat 
stud  Iris. 

One  branch  of  the  Ocular  Artery,  called  Centralis  Retina, 
perforates  the  Optic  Nerve,  and  is  difperfed  upon  the  Retina. 

The  Veins  which  correfpond  with  the  Arteries  of  the  Eye, 
communicate  freely  with  each  other,  and  pafs  partly  to  the  Exter- 
nal jugular  Vein,  by  branches  fituated  about  the  fore-part  of  the 
Orbit,  and  partly  to  the  Internal  Jugular  Vein  by  the  Cavernous 
Sinus. 

NERVES  OF  THE  EYE. 

Befdes  the  Optic  Nerve,  already  taken  notice  of,  the  Eye  re- 
ceives the  Third  and  Fourth  Pairs,  and  branches  from  the  nrft 


part  of  the  Fifth  Pair,  together  with  the  Sixth  Pair,  and  branch- 
es from  the  Seventh. 

The  parts  about  the  fore-fide  of  the  Orbit  are  fupplied  by 
branches  from  the  Fifth  and  Seventh  Pairs; — the  Ball  of  the  Eye 
by  Nerves  called  Ciliary,  wtfch  come  from  the  Third  and  Fifth 
Pairs; — the  fat,  Mul  les,  Lacrymal  Gland,  &c.  are  fupplied  by 
the  Third,  Fourth,  Fifth,  and  Sixth  Pairs. 

The  ufe  of  the  Eye  is,  to  receive  and  colleft  the  rays  of  light, 
in  fuch  a manner  as  to  form  upon  the  Retina  the  image  or  picture 
of  the  object.  which  the  Eye  looks  at ; and  the  point  where  thefe 
different  lays  meet  is  called  the  Focus. 

T he  object  is  painted  upon  the  Retina  in  an  inverted  manner, 
the  rays  from  above  failing  upon  its  under,  and  thole  from  be- 
low upon  its  upper  part;  and  it  is  fuppol'ed  to  be  by  habit,  or 
rather  by  in  ft  in  £1,  that  we  judge  of  the  rcalFw  nation  of  any  ob- 
ject. 

That  the  rays  of  light  may  terminate  diftin£Vly  or  the  Retina, 
it  isnecedary  that  both  the  Cornea  and  Cryftalitne  Lens  (hould 
have  a certain  degree  of  convexity. 

If  either  the  one  or  the  other  be  too  prominent,  the  Focus  will 
be  formed  before  it  reach  the  Retina,  as  is  the  cafe  in  ftiort-fight- 
ed  people,  who  require  concave  glafles  to  enable  them  to  fee  ob- 
je£ts  diftiinStly,  at  the  proper  and  ordinary  diftance. 

If,  on  the  contrary,  the  Cornea  or  Lens  be  too  flat,  or  the 
refractive  power  of  the  Humours  be  in  any  way  dimir.ifbed,  the 
Focus  will  then  be  imperfeCtly  formed,  till  the  objedft  is  viewed  at 
a greater  diftance  than  ordinary,  as  is  the  cafe  with  perfons  ad- 
vanced in  life,  to  whom  the  afliftance  of  convex  glafles  become* 
neceflary. 

How  an  objeCt,  viewed  with  both  Eyes,  appears  Angle,  has 
been  afcribed  by  the  generality  of  Authors  to  cuflom  and  habit ; 
and  by  others  to  inftinCt,  which  regulates  the  uniform  motion  of 
the  Eye,  and  the  accurate  application  of  both  to  one  point. 

The  Eye  is  enabled  to  judge  of,  or  accommodate  itfeif  to  ob- 
jects at  different  diftances,  by  the  aCtion  of  its' Mufcles  increa- 
flng  or  diminifhing  the  length  of  its  Axis,  and  by  the  motions  of 
the  Iris  allowing  a greater  or  fmaller  quantity  of  light  to  be 
thrown  into  the  Eye. 


40 


OF  TIIE  NOSE. 


Th'S  Nofe,  which  is  the  Organ  of  Smell,  and  contributes  to 
the  general  purpofe  of  Refpiration,  is  divided  into  the  External 
Prominent  Part,  and  the  Internal  Cavity,  which  is  feparated  by 
the  Septum  Naiium  into  two  fmaller  Cavities  ; — or,  it  is  divided 
into  Hard  and  Soft  parts. 

The  External  part,  or  Nofe,  properly  fo  called,  is  compofed 
fuperiorly  of  Bones,  inferiorly  of  Cartilages,  and  has  a partial 
covering  from  the  Mufcles,  and  a general  one  from  the  common 
Integuments. 

On  the  ontfide  of  the  Nofe  are  obferved, — the  Radix , or  upper 
part  j — the  Dorfutn,  or  middle  prominence  ; — the  Apex,  or  point  ; 
—the  Alee,  or  lateral  moveable  parts and  Columna,  or  under 
part  of  the  Partition  next  the  Upper  Lip. 

The  Ofleous  part  of  the  Nofe  is  formed  by  the  OJfa  Naji,  pro- 
perly fo  called,  the  OJfa  Maxillaria  and  Os  Frontis,  whieh  con- 
ftitute  the  upper  and  fore-part  : 

By  the  Os  Ethmoides  and  OJfa  Unguis,  which  form  the  upper, 
inner,  and  lateral  paits: 

And  by  the  OJJ'a  Maxillaria  Superioria,  OJjfa  Palaii,  Os  Spke- 
Koides , OJfa  Spongiofa  Inferiora,  and  Vomer,  which  form  the  un- 
der, inner,  and  back-part. 

The  two  Cavities,  or  Nojlrils,  terminate  anteriorly  in  the  Face, 
and  pofteriorly  in  the  Fauces,  and  are  much  enlarged  by  the  dif- 
ferent Sinufes  which  communicate  with  them. 

The  under  and  fore  part  of  the  Nofe  confifcs  of  five  Cartilages, 
cf  a fomewhaL  regular  figure,  and  of  forne  fmaller  pieces,  which 
are  more  in  egu  :ar,  and  of  ar.  indeterminate  number. 

Of  the  five  Cartilages,  one  is  iituated  in  the  middle,  and  the 
other  four  laterally. 

The  middle  Cartilage  is  the  molt  confi'derable,  and  fupports 
the  reft  : It  conftitutes  the  Cartilaginous  part  of  the  Septum  Nari- 
um,  and  is  joined  to  the  anterior  edte  of  the  Natal  Lamella  of  the 
Ethmoid  Bone,  to  the  anterior  edge  of  the  Vomer,  and  to  the 
fore-part  of  the  Spinous  Procefs  of  the  Superior  Maxillary 
Bones. 

Of  the  lateral  Cartilages,  two  are  placed  anteriorly,  form'ng 
by  their  curved  union  the  Tip  of  the  Nofe  ; and  two  pofteriorly, 
which  form  the  Alae  Nali. 


41 


• ' jg»  m 

Between  the  anterior  and  pofterior  Cartilages,  are  fpaces 
filled  with  additional  Cartilages,  the  number,  fize,  and  figure, 
■varying  in  different  bodies. 

The  el.fticity  of  the  Cartilages  contributes  to  the  defence  of 
the  Nofe  againft  external  injuries. 

The  Nofe  is  covered  by  the  common  Integuments,  and  per- 
forated at  its  under  and  outer-part  by  the  Duffs  of  Sebaceous 
Glands,  the  contents  of  which  may  be  readily  fqueezed  out  by 
the  preffure  of  the  Fingers. 

The  Cartilages  of  the  Nofe  are  moved  in  different  directions, 
by  the  following  Mulcle;,  which  have  been  alieady  deter. bed, 
viz.  the  Comprejfor  Ndriutn,  the  Nafal  part  of  the  Frontal  Mufcie, 
the  Levator  and  Depref'or  Labii  Superior  is  Alaqui  Naji. — The 
Nofe  may  alfo  be  moved  by  the  neighbouring  Mufcles,  which, 
in  many  inflances,  become  affiftants  to  the  others. 

The  internal  Nares  or  Cavities  of  the  Nofe  extend  upwards  to 
the  Cribriform  Plate  of  the  Ethmoid,  and  to  the  Body  of  the 
Sphenoid  Bone. 

At  the  inner  fide  they  are  bounded  by  the  feptum  Narium, 
which  is  formed  by  the  Nafal  Lamella  of  the  Ethmoid  Bone, 
by  the  Vomer,  and  by  the  middle  Cartilage  of  the  Nofe. 

On  the  outfide,  or  that  next  the  Cheek,  the  Ofla  Spongiofa 
projeft  a considerable  way  into  their  Cavities,  and  increafe  the 
Surface  of  the  Membrane  of  the  Note,  for  enlarging  the  Organ 
of  Smell. 

In  animals  which  fmell  acutely,  the  Ofla  Spongiofa  are  re- 
maikably  large  and  complex. 

The  bottom  of  the  Noftrils  runs  directly  backwards,  fo  that  a 
flraight  probe  may  be  palled  through  either  of  them  to  the 
Throat. 

In  the  fore-part  of  the  Noftrils  there  are  (1  iff  Hairs,  called 
VibriJJ'ee,  which  prevent  the  Mucus  from  conftantly  flowing  out, 
and  infers,  or  other  extraneous  matter  from  entering. 

The  general  Cavity  of  each  Neftrii  is  divided  by  the  Ofla  Spon- 
giofa into  three  Meatus,  or  Pajfages,  which  run  from  before  back- 
wards, and  are  defc; ibecJ  by  Haller  according  to  their  fixa- 
tions, viz. 

The  Meatus  Narium  Superior , placed  at  the  upper,  inner,  and 
back-part  of  the  Superior  Spongy  Bone. 

The  Meatus  Meditis,  fituated  between  the  Superior  and  Infe- 
rior Spongy  Bones. 

The  Meatus  Inferior,  fituated  between  the  Inferior  Spongy 
Bone  and  bottom  of  the  Nofe. 

The  inlide  of  the  Nofe  is  lined  with  a thick  Spongy  Membrane, 
termed  Mucofa,  or  Pituitaria  cf  Schneider,  or  Schneideri- 
an a,  which  lines  the  whole  internal  Nares,  and  is"  alfo' continued 


VOL.  II. 


to  the  different  Sinufes,  to  the  Le.crymal  Sacs  and  Palatine  Du£ts, 
to  < he  Pharynx,  Palate,  and  Euftachian  Tubes. 

This  Membrane  is  veiy  Vafcular  and  Nervous,  and  is  the  pri- 
mary Oigan  of  Smeil  ng.  It  is  conftantly  lubricated  and  pre- 
ferred in  a proper  degiee  of  moifture  by  the  Mucus  of  the  Nofe, 
which  is  dil’chaiged  upon  its  Surface  from  numerous  finall  Fol- 
licles. • 

The  different  Sinufes  of  the  Bones  of  the  Head,  after  having 
run  obliquely  backwards  in  a Iho  it  winding  direftion,  terminate 
by  fjnall  openings  in  the  Cavity  of  the  Nofe. 

The  Frontal  Sinufes  pal's  downwards  into  the  anterior  Ethmoid 
Cells,  which  terminate  in  the  upper  part  of  the  Nofe,  behind 
the  beginning  of  the  Lacrymal  Sacs. 

Befider.  the  P.flages  common  to  the  Frontal  Sinufes  and  ante- 
rior Ethmoid  Cells,  there  are  others  proper  to  the  P interior  Eth- 
moid Cells,  which  terminate  in  the  upper  and  back-part  of  the 
Nofe,  near  the  openings  of  the  Sphenoid  Sinufes. 

The  Sphenoid  Sinufes  op^n,  behind  the  Cells  of  the  Ethmoid 
Bone,  into,  the  upper  and  bar  k-part  of  the  Nofe. 

The  Maxillary  Sinufes  open  at  their  upper  and  inner  fidcs,  by 
one,  and  fometimes  two  pillages,  into  the  m ddle  of  the  ipace 
between  the  Superior  and  Interior  Spongy  Bones,  nearly  oppo- 
fite  to  the  under  ed  e of  the  Orbits. 

At  the  upper  part  of  the  Maxillary  Sinufes,  Appendices,  deferi- 
bed  by  Haller,  are  fometimes  found,  which  commun  cate  with 
the  Ethmoid  Cells. 

The  Sides,  or  Walls  of  the  Maxillary  Sinufes,  are  formed  of 
thin  Plates  of  Bone,  excepting  where  the  Pioc-efles  project  and 
give  them  additional  ftrength.  Below,  they  have  only  thin  Plates 
between  them  and  the  Dentes  Molares,  the  roots  of  which  are 
fometimes  found  to  perforate  the  Septum. 

The  different  Sinufes  are  lined  with  a continuation  of  rheMem- 
brana  Scbneideriana  ; but  in  thefe  it  is  thinner,  lefs  Vafcularand 
Nervous,  than  that  part  of  the  Membrane  which  lines  the  gene- 
ral Cavity  of  the  Nofe. 

They  are  conftantly  moiftened,  but  not  filled  with  a fluid. 

The  Sinufes  increafe  and  modulate  the  voice  : Their  hollow 
ftrufture  renders  the  Bones  lighter ; but  they  do  not  appear  to 
conftitute  part  of  the  Organ  of  Smell 

Their  paffages  being  directed  backwards,  prevent  any  kind  of 
extraneous  matter  from  getting  into  them. 

The  Lacrymal  Sac  is  a Membranous  Canal,  fituated  in  the 
Lacrymal  Groove,  formed  by  the  Superior,  Maxillary,  Lacry- 
mal, and  Infeiiur  Spongy  Bones. 

TJie  Ojfeous  Du6l,  in  its  defeent,  runs  a little  obliquely  back- 
wards to  the  lower  and  lateral  part  of  the  Cavity  of  the  Nole, 
where  it  terminates  at  the  inner  and  fore-part  of  the  Antrum 
Maxillare,  under  the  Os  Spongiofum  lnferius,  a little  behind 


45 


the  anterior  extremity  of  that  Bone,  and  in  a direct  line  upwards 
from  the  fecond  Dens  Molaris. 

The  upper  part  of  the  Offeous  Paffage  forms  only  a femi-canal, 
the  under  end  a complete  one. 

The  Lacrymal  Sac  is  lituated  in  the  upper  part  of  the  Lacry- 
mal  Gru  ve,  behind  the  Tendon  of  the  Orbicularis  Mul'cle  of 
tke  Eye-lids.  About  a fourth  part  of  the  Sac.  is  fituated  above 
the  Tendon,  forming  a kind  of  InteJUnum  Cacurn,  and  the  reft  is 
placed  below. 

Towards  the  inner  angle  of  the  Eye,  behind  the  Tendon  of 
the  Orbicularis  JMiifcle,  the  Sac  is  perforated  by  the  Lacrymal 


The  under  part  cf  the  Sac  becoming  a little  narrower,  but 
without  forming  any  Vasve,  paffes  into  the  Note,  under  the  name 
of  Lacrymal  Duct , Canalis  Nafalis,  or  DuHus  ad  Nafum,  and 
term  nates  at  the  inferior  extremity  of  the  Offeous  Canal. 

The  iubftance  of  the  Lacrymal  Sac  and  Duft  is  fimilar  to  that 
of  the  Membrana  Schneider tana,  is  deiended  with  the  fame  kind 
of  Mucus  with  which  this  Membrane  is  lubricated,  and  is  firmly 
connected  to  the  Periofteum  of  the  Offeous  Canal. 

The  ufe  of  this  paffage  is, — to  convey  the  fuperfluous  Tears 
to  the  Nofe,  fo  as  to  prevent  them  from  palling  over  the  Cheek. 

The  DuBus  Incijivus,  or  Nafalo  Palatinus  of  fcTENO,  is  a 
fmall  Canal,  whicn,  as  has  been  already  oblerved  in  the  defcrip- 
tion  of  the  Bones,  is  only  fomet  mes  met  with  in  the  Hu/nan 
Body,  though  it  is  always  to  be  found  in  the  Ox,  Horfe,  Sheep, 
&c. 

When  prefent,  it  takes  its  origin  from  a fmall  Pit,  formed  in 
the  fore-part  of  the  bottom  of  the  Noftril,  under  the  termination 
of  the  Lacrymal  Duft.  It  runs  obliquely  downwards  and  for- 
wards, placed  in  fuch  a manner  as  to  receive  and  conduit  Tears 
into  the  Mouth. 

The  Arteries  of  the  Nofe  come  chiefly  from  the  external  Ca- 
rotids. 

Thufe  of  the  outer  part  of  the  Nofe  come  from  the  Facial  and 
Internal  Maxillary  Arteries; — thofe  of  the  inner,  from  the 
Maxiilares  Internae; — and  a few  twiDs  are  furnifhed  by  t lie  Ocu- 
lar Arteries. 

The  Feins  go  to  the  External  Jugulars  ; — they  likewife  com- 
municate with  the  Ocular  veins,  and  of  cotirle  with  the  Lateral 
Sinufes  and  Internal  Jugul  rs. 

The  Nerves  with  wh  ch  the  outer  part  of  -the  Nofe  is  chiefly 
fupvlied,  come  from  the  fecond  branch  of  the  Fifh,  ar.d  from 
the  Port  o Dura  of  the  Seventh  Pa  r. 

The  inner  part  is  principally  i'upplied  by  the  Firft,  or  OlfaSory 
Nerves,  and  by  fame  branches  from  the  firlt  and  fecond  portions  of 
the  Fifth  Pair. 


Dufts 


44 


OF  THE  EAR. 


The  Ear,  or  Organ  of  Hearing,  is  divided  into  the  External 
and  Internal  Ear. 

EXTERNAL  EAR. 

The  External  Ear  comprehends  the  Auricle,  or  Ear,  properly 
fo  called,  and  the  Meatus  Auditorius  Externus. 

It  is  again  divided  into  the  Pinna,  or  Ala,  which  conftitutes 
by  much  the^reater  part  of  it  ; — and  Lobus,  which  is  placed  at 
its  under  end. 

Tlie  Pinna  or  Ala,  is  chiefly  compofed  of  Cartilage,  and  is 
divided,  at  its  fore-part,  into  i'evera]  Eminences  and  Cavities, 
which  have  obtained  particular  names,  viz. 

The  Helix,  or  outer  Bar,  or  Margin,  fo  called  from  'ts  wind- 
ing dii  edtion.  It  ariles  beh  nd  at  the  Lobe  of  the  Ear,  furrounds 
its  upper  edge,  and  termm  tes  below,  nearly  oppofite  to  its  ori- 
gin, divid  n the  Concha  into  two  paits. 

The  Antihelix,  Authelix,  or  inner  Bar  or  Mar  .■•in,  which  is 
fituated  within  tiie  former,  and  is  compoied  fuperiorly  of  two 
Rid  ges,  un  ting  together  below. 

The  Tragus,  fo  called  from  the  Hairs  which  frequently  grow 
from  it  having  a refemblance  to  the  beard  of  a Goat. 

It  is  a ftnall  Eminence  which  lies  over  the  Meatus  Externus, 
and  is  connefled  to  the  under  and  fire-part  of  the  Helix. 

The  Antitragus,  fo  named  from  its  being  oppolite  to  the  Tra- 
gus, below  the  pollerior  ext.emuy  of  the  Antihelix. 

The  Cavitas  lunominata,  fituated  between  the  Helix  and  An- 
tihelix. 

T e Scapha,  or  FoJJ'a  davicula.is, — compared  in  fiiape  to  that 
of  a B a., — iitua  ed  between  the  two  1 mbs  of  the  Antihelix. 

The  Concha,  fo  tailed  from  its  refemblance  to  a F fb-fhell  of 
that  name.  It  is  a la  ge  Cavity  under  the  Amihclix,  divided 
by  the  Helix  ntotwopa.ts,  the  inferior  of  which  leads  to  the 
Mea'  ue  Au  .ilorius. 

The  back  part  of  the  External  Ear  exhibits  only  one  confi- 
de) able  Eminence,  which  is  the  convex  Surface  of  the  Concha.  t 

The  Lobus , which  is  the  inferior  foft  p.ut  of  the  Ear,  is  com- 
pofed of  Cellular  Subfiance,  with  a tin  all  quantity  of  Fat. 


45 


The  Ear  is  covered  by  a continuation  of  the  common  Integu- 
ments, which  is  thinner  here  than  on  the  reft  of  the  Body,  and  is 
perforated  in  many  parts  by  the  mouths  of  Sebaceous  Dufts, 
which  are  placed  immediately  under  the  Skin. 

The  motions  of  the  Ear,  which  are  very  limited,  are  regulated 
by  levergi  Milfcles,  fome  of  which  are  common  to  the  Ear  and 
Head,  and  others  proper  to  the  Ear  itfelf.  The  common  Muf- 
cles  have  been  already  defcribed.  The  Mufcies  proper  to  the 
Ear  lie  ctofe  upon  the  Cartilage,  and,  in  the  generality  of  fub- 
jefts,  are  fothin,  white,  and  indiftinft,  as  to  receive  from  fome 
Authors  the  name  of  Mufcular  Membranes. — They  are  as  follow. 

Helicis  Major. 

Origin:  From  the  anterior  acute  part  of  the  Helix,  upon 
which  it  afeends. 

Insertion  : Into  the  Helix.  ...  .. 

ASiion:  To  pull  that  part  into  which  it  is  inferied  a little 
downwards  and  forwards. 

Helicis  Minor. 

Origin  : From  the  under  and  fore-part  of  the  Helix. 

Infertion  : Into  the  Helix,  near  the  Filfure  in  the  Cartilage  op- 
pofite  to  the  Concha. 

ASion  : To  contract  the  Fift'ure. 

Tragicus. 

Origin:  From  the  middle  and  outer  part  of  the  Concha,  at 
the  root  of  the  Tragus,  along  which  it  runs. 

Infertion  : Into  the  point  of  the  Tragus. 

Action  : To  pull  the  point  of  the  Tragus  a little  forwards. 

Antitragicus. 

Origin.  From  the  internal  part  of  the  Antitragus,  upon  which 
it  runs  upwards. 

Infertion  : Into  the  t;p  of  the  Antitragus,  as  far  as  the  in- 
ferior part  of  the  Antihelix,  where  there  is  a Fift'ure  in  the  Car- 
tilage. - 

ASion:  To  turn  the  tip  of  the  Antitragus  a little  outwards, 
and  deprefs  the  extremity  of  the  Antihelix  towards  it. 

Transversus  Auris. 

Origin  From  the  prominent  part  of  the  Concjia,  on  the  Dor- 
fum,  or  back  part  of  the  Ear. 

Injertion  .-  Into  the  outhde  of  the  Antihelix. 

ASion:  To  draw  the  parts  to  which  it  is  connefted  towards 
each  other,  arid  to  (fretch  the  Sea.  ha  and  Concha. 

The  ufe  of  the  External  Ear  is  to  crdleft  the  found,  and  con- 
vey it  to  the  Meatus  Externus, — the  Mufcies  giving  tenlion  to 
it,  fo  as  to  render  the  founds  more  diltinfl. 


% At 


46 


The  Cartilage  of  the  External  Ear  is  conneEled  to  the  Tem- 
poral Bone  by  the  common  Integuments,  and  by  its  Mulcles; 
and  is  fumiihed  with  Ligamentous  Membranes,  which  fix  it  to 
the  roots  of  the  Zygoma  and  of  the  Mafto-d  Procefs. 

The  Meatus  Auditorious  Bxternus  leads  inwards,  from  the 
Concha,  and  in  i s courfe  proceeds  forwards  and  upwards,  turn- 
ing a little  downwards  at  its  farth'eft  extremity,  and  terminating 
at  the  Membrana  Tympani. — The  turns,  however,  are  fo  in- 
confiderable,  that  the  bottom  of  the  paffage  cun  be  readily  leen  in 
a clear  light,  upon  pulling  the  ear  backwards.. 

It  is  lbmewhat  of  an  oval  form,  a 1 ttle  comra&ed  in  the  mid- 
dle, and  upwards  of  an  inch  in  length. 

Its  outer  end,  which  is  a continuation  of  the  Concha,  is  Car- 
tilaginous, and  has  two  or  tjyce  Interruptions  or  Fijfures  in  it. 

On  the  upper  and  back-part  of  its  circumference,  there  is  a 
Large  Interruption  terminating  in  an  oblique  M.-rgin,  which  is 
tixed  to  the  rough  edge,  at  the  under  part  of  the  Offeous  portion 
of  the  Meatus. 

At  the  upper  and  back-part  of  the  Meaius,  the  Cartilage  has 
but  Jittle  connection  with  the  Bones,  being  there  fixed  by  the 
Skin  which  lines  the  Canal. 

The  Offeus  Canal  is  continued  from  the  Cartilage  of  the  Mea- 
tus, and  is  the  longer  of  the  two,  particularly  at  the  upper  and 
back-part  of  the  Paffage. 

The  Meatus  is  lined  with  a continuation  of  the  Skin,  which 
fills  up  the  interruptions  in  the  Cartilage,  but  is  thinner  than 
on  the  reft  of  the  Body. 

Under  the  Skin  of  the  Meatus,  and  near  its  outer  end,  there 
are  numerous  fmall  glands,  of  a yellowifh  colour,  placed  in  a 
Reticular  Subftance,  formed  of  the  Corpus  Mucofum,  and  termed 
Glandules  Cerutninofa,  which  difeharge  the  Wax  of  the  Ear 
through  fmall  Excretory  DuCIs. 

The  Arteries  of  the  External  Ear  come  anteriorly  from  the 
Temporal,  and  posteriorly  from  the  Occipital,  both  of  which  are 
branches  of  the  External  Carotid  Artery. 

The  Veins  pafs  partly  to  the  External,  and  partly  to  the  In- 
ternal Jugulars. 

The  fore-part  of  the  Ear  is  fupplied  with  Nerves  from  the 
third  or  the  Fifth,  and  from  the  Po'rtio  Dura  of  the  Seventh 
Pair  5 the  under  and  back-part,  by  branches  from  the  firft  and 
f'econd  Cervicles. 

The  Meatus  Exfernus  conveys  the  found  from  the  Outer  to- 
wards the  Inner  Ear,  and  i6  fuppofed  to  do  this  to  greater  ad- 
vantage, on  account  of  the  winding  nature  of  the  Paffage. 

The  Wax  lubricates  the  Paffage,  and  defends  it  from  the  in- 
juries of  the  air,  and  being  of  a vifeid  and  bitter  quality,  affifts 
in  the  exclufion  of  infefts. 


47 


In  the  Foetus,  the  Meatus  is  entirely  Cartilaginous,  and  only 
adheres  to  an  imperfect  Bony  Circle,  in  which  the  Membrana 
Tympani  is  fixed. 

At  the  inner  end  of  the  Meatus  Externus,  the  Membrana 
Tympani  is  fituated,  which  has  its  name  from  covering  the  outer 
part  of  the  Tympanum  or  Drum  of  the  Ear. 

It  is  firm,  almoft:  tranfiiarent,  and  of  an  oval  form. 

's  fixed  in  a Groove  which  divides  the  Meatus  from  the 
Tympanum. 

It  is  very  tenfe,  but  has  a finall  deprejjion  in  the  middle  next 
the  Meatus,  with  a correfpondiug  convexity  towards  ,he  Tym- 
panum, where  the  extremity  of  the  Malleus  is  fixed  to  it. 

Its  fituation  is  fomewat  oblique,  the  upper  part  being  turned 
outwards,  and  the  under  inwards,  To  that  the  lower  lide  of  the 
Meatus  is  a little  longer  .han  the  upper. 

It  forms  a complete  Septum,  and  has  no  hole  in  it,  fuch  as  has 
been  del'cribed  by  lome  Authors. 

It  is  formed  partly  ofa  continuation  of  the  Lining  of  the  Mea- 
tus, but  chiefly  of  the  Periofteum. 

The  Membrma  Tympani  has  numerous  finall  Veffels  from  the 
Temporal  and  Stylo- maftoid  Arteries,  which  run  m a radiated 
manner,  and  which  are  moft  abundant  in  the  Fcetus. 

It  is  the  Conduftor  of  Sound  from  the  Outer  to  the  Inner 
Ear. 

In  the  Foetus,  this  Membrane  is  fixed  in  an  impeTeft  R'rtn- 
of  Bone,  and,  along  with  the  Meatus,  is  covered  with  a Mut 
cus  Membrane,  which  defends  the  parts  from  the  too  ftrong 
impulfe  of  Sound. 

THE  INTERNAL  EAR. 

The  Internal  Ear  comprehends  the  Tympanum,  Labyrinth,  and 
certain  PaJJ'ages'  leading  into  thefe. 

The  Tympanum,  or  Drum  of  the  Ear,  is  fituated  at  the  inner 
fide  of  the  Membrana  Tympani,  approaches  to  a hemifpherical 
figure,  and  is  about  half  an  inch  in  width. 

Btween  the  Tympanum  and  Cavity  called  Labyrinth,  there  is 
an  OJJeous  Septum,  which  forms  the  bottom  of  the  Tympanum, 
where  there  are  feveral  Eminences,  viz. 

The  Promontory,  which  forms  the  be'ginr:in«  of  the  Scala 
- ympani,  and  divides  the  Tympanum  into” anterior  and  pofterior 
regions. 

A Protuberance  at  the  upper  and  back-part  of  the  Tympanum, 
formed  by  the  Aquseduftus  Fallopii. 

A Projection,  called  Eminentia  tyramidalis  Tympani,  fituated 
behind  the  Feneltra  Ovalis,  in  which  is  the  Paffage  for  the  Sta- 
pedius Mulcic. 


4S 


An  Eminence  at  the  upper  and  fore-part  of  the  Tympanum, 
containing  a iemi  canal,  for  lodging  part  of  the  Tenfor  Tym- 
pani  Mufcle. 

In  the  Tympanum  there  are  various  Paffages,  which  communi- 
cate with  the  neighbouring  parts,  viz; 

The  Iter  a Palato  ad  Aurem,  or  Eujlachian  Tube,  which  goes 
off  from  the  upper  and  fore- part  of  the  Tympanum,  and  runs 
obliquely  forwards  and  inwards  to  the  poiterior  opening  of  the 
Nollril,  and  terminates  at  its  outer  edge,  above  the  arch  of  the 
Palate. 

The  po'fterior  part  of  the  Tube  is  formed  in  the  Pars  Petrofa, 
at  the  upper  and  outer  part  of  the  Canal  for  the  Carotid  Artery, 

The  anterior  portion  is  formed  above,  by  the  Spinous  Procefs, 
and  root  of  the  Pterygoid  Procefs  of  the  Sphenoid  Bone  ; — and 
below,  by  Cartilage  and  Membrane. 

It  is  narrow  next  the  Ear,  where  it  can  only  admit  the  point 
of  a Surgeon’s  probe  ; but  becomes  gradually  wider  towards  the 
Nofe,  where  it  terminates  by  an  oblique  opening  with  prominent; 
fides,  fufficiently  large  to  admit  a Goofe-quill. 

It  is  lined  by  a Membrane  fimilar  to  that  of  the  Nofe,  of 
which  it  appears  to  be  a continuation  ; and  on  the  edge  of  the 
Mouth  of  the  Tube,  it  is  fo  thick  as  to  add  confiderably  to  its 
prominency. 

The  Euiiachian  Tube  preferves  the  balance  of  Air  between  the 
Outer  and  Inner  Ear,  and  prevents  it  from  preffingtoo  forcibly 
upon  the  different  Membranes  placed  in  the  fides  of  the  Tym- 
panum. 

It  has  been  fuppofed  to  convey  the  found  of  a perfon’s  own 
Voice  to  the  Inner  Ear;  but  experiment  does  not  favour  this 
opinion,  nor  is  it  found  to  render  Sound  more  diftinft  when  the 
Mouth  is  open  ; — though  perl’ons  who  are  dull  of  hearing  'are  ob- 
ferved  frequently  to  liften  after  this  manner. 

The  Cells  of  the  Mafioid  Procefs,  which  open  into  the  upper 
and  back-part  of  the  Tympanum,  oppofite  to,  but  a little  higher 
than  the  Euftachian  Tube. 

They  are  very  irregular,  and  have  many  windings  and  turn- 
ings, which  communicate  freely  with  each  other,  and  are 
lined,  like  the  Cells  of  other  Bones,  with  the  Periofteum  In- 
ternum. 

They  nfiift  the  Tympanum  in  refle&ing  the  Sound. 

In  Quadrupeds  which  hear  acutely,  there  are  large  Cavities 
connefted  with  the  Tympanum,  which  feem  to  fupply  the  place 
of  Maftoid  Cells. 

Above  the  Promontory,  a Hole,  called  Fenefra  Ovalis,  the 
upper  and  under  edges  of  which  are  convex  upwards, — for  lodg- 
ing the  Bale  of  the  Stapes. 

The  inner  edges  of  this  Hole  are  contracted  bv  a narrow  bor- 
der, upon  which  the  end  of  the  Stapes  reds. 


49 


Below  the  Fenellra  Ovalis,  and  at  the  under  and  back-part  of 
the  Promontory,  a Hole,  final ler  than  the  former,  called  FeneJ 
tra  Rotunda. 

It  is  ('laced  obliquely  backwards,  and  outwards,  leads  to  the 
Cochlea,  but  is  Ihut  up  by  a Membrane  which  affifts  in  com- 
municating Sound  to  the  Labyrinth. 

1 he  Sides,  or  Walls  of  the  Tympanum,  which- likewife  affiftin 
conveying  Sound  to  the  Labyrinth,  are  lined  with  Periofteum, 
which  isreflefted  into  the  different  Paffages  leading  from  it. 

The  Cavitv  of  the  Tvmpanum  contains  four  fmall  Bones, 
called  Officula  Auditus,  which  form  a chain  ftretching  acrofs  from 
the  Membiana  Tympani  to  the  Labyrinth. 

The  OJJirula  Auditus  are, — -the  Malleus,  the  Incus,  the  Os  Or- 
biculare, and  the  Stapes ; — ;htfe  names  being  derived  from  lub- 
ftances  whi  'h  they  are  fuppofed  to  refemble  in  fhape. 

The  Maileous,  or  Hammer,'  confifts  of  a round  Head,  a fmall 
Neck,  a Manubrium  or  Handle,  and  two  fmall  Procefles,  one  in 
the  neck,  long  and  vei  y llender,  and  therefore  called  Gracilis  } 
the  other  in  the  upper  end  of  the  Handle,  called  ProceJJiu  brevis. 

The  Handle  is  by  fome  Authors  conftdered  as  one  of  the  Pro- 
cefies,  and  is  then  called  the  longeft  of  the  three.  It  forms  an 
angle  with  the  Neck,  becomes  gradually  fmaller,  and  is  bent,  at 
its  extremity,  towards  the  Membraria  Tympani. 

In  the  natural  fituation,  the  Head  is  turned  upwards  and  in- 
wards, and  the  Handle  down  upon  the  Membrana  Tympani,  to 
which  it  adheres. 

The  Incus,  compared  in  fhape  to  an  Anvil,  but  more  refem- 
bling  one  of  the  Dentes  Molares,  with  its  roots  widely  fep3rated, 
is  lituated  behind  the  Malleus,  and  is  formed  of  a Body,  and 
tvio  Crura  of  unequal  lengths. 

The  Body  has  a Cavity  and  tvjo  Eminences , correfponding  to 
that  part  of  the  Malleus  with  wh-ch  it  is  articulated. 

The  fhort  Crus  extends  backwards,  and  is  joined  by  a Liga- 
ment to  the  edge  of  the  Maltoid  opening. 

The  long  Crus  is  turned  downwards,  with  the  point  a little 
flattened,  and  bent  inwards. 

The  Os  Orbiculare  is  the  fmalleft  Bone  of  the  Body,  being 
confiderably  lefs  than  a grain  of  Muftard-feed. 

It  is  articulated  with  the  point  of  the  long  Procefs  of  the  Incus, 
and  is  fo  firmly  fixed  to  it,  that  in  feparating  the  fmall  Bones  of 
the  Ear  from  each  other,  it  is  apt  to  adhere  to  the  Incus,  and  has 
on  this  account  been  frequently  coniidered  as  a Procefs  of  that 
Bone. 

The  Stapes  is  named  from  a ftriking  refemblance  it  has  to  a 
Stirrup.  It  is  divided  into  Head,  Crura , and  Bafe. 

The  Plead  is  placed  upon  a fmall  flat  neck,  and  is  articulated 
with  the  Os  Orbiculare. 

Vol.  II.  E 


50 


The  Crura,  like  thofe  of  the  Incus,  are  unequal  in  length, 
and  have  a groove  \viihin;  which  is  occupied  by  a Membrane. 

The  Safe  is  of  an  oval  fliape,  and  has  no  perforation  in  it. 
Its  edges  correfpond  with  thofe  of  the  Feneftra  Ovalis,  with 
which  it  is  articulated. 

The  Stapes  is  placed  horizontally,  being  nearly  at  a right  angle 
with  the  inferior  Crus  of  the  Incus. — Its  two  Crura  are  placed 
•in  the  fame  plane, — the  longed  backwards. 

The  final i Banes  of  the  Ear  are  articulated  with  each  other 
by  Capfular  Ligaments,  proportioned  to  their  fize,  and  are  cover- 
ed by  the  Periofteum,  which  likewife  fixes  them  to  the  Mem- 
brana Tympani  and  Feneftra  Ovalis. 

Die  fmall  Bones  have  the  following  Mufcles  fixed  to  them, 
which  ferve  for  their  different  motions. 

Tensor  Tympani,  or  Internus  Auris. 

Origin:  From  the  Cartilaginous  extremity  of  the  Euftachian 
Tube,  near  the  entry  of  the  Artery  of  the  Dura  Maier.  From 
thence,  its  Fle/hy  Belly  runs  backwards  in  a Canal  peculiar  to 
it,  at  the  upper  and  inner  part  of  the  Olfeous  Portion  of  the 
Tube,  being  covered  only  by  a thin  plate  of  Bone.  It  fends  off 
a (lender  Tendon,  which  makes  a turn  in  the  Tympanum,  and 
paffes  outwards. 

Infertion  : Into  the  pofterior  part  of  the  Handle  of  the  Malleus, 
a little  below  the  root  of  its  long  Procefs. 

ASlion : To  pul!  the  Malleus  and  Membrana  Tympani  in- 
wards by  which  the  Membrane  is  rendeied  more  concave  and 
tenfe,  and  better  adapted  for  the  impieflion  of  weak  founds. 

Laxator  Tympani. 

Origin  : By  a very  fmall  beginning,  from  the  extremity  of  the 
Spinous  Procefs  ot  the  Sphenoid  Bone,  behind  the  entry  of  the 
Artery  of  the  Dura  Mater  ; after  which  it  runs  backwards  and  a 
little  u p wards,  at  the  ou  tilde  of  the  Eu  It  a chi  an  T ube,  in  a FifTnre 
of  the  Os  Temporis,  near  the  Foffa  which  lodges  the  Condyle  of 
the  Lower  Jaw 

Infertion:  Into  the  long  Procefs  of  the  Malleus,  within  the 
Tympanum. 

Affion  : To  draw  the  Malleus  obliquely  forwards  and  outwards, 
and  thereby  to  render  the  Membrana  Tympan i lefs  convex,  or  to 
relax  it  when  Sounds  are  too  ftrong. — Haller  denies  the  ex- 
iftence  of  Mufcular  Fibres  in  this  Subltance. — Sabatier  de- 
fcribes  it,  but  doubts  of  its  Mufcularity. 

Stapedius. 

Origin  ; By  a fmall  Flefhy  Belly,  from  a little  caver  n in  the 
Pars  Petrofa,  near  the  Cells  of  the  Maftoid  Procefs.  Its  Ten- 


5 L 


don  pafies  forwards  through  a final!  Hole  in  that  Cavern,  and- 
goes  into  the  Tympanum. 

I : Tertian  : Into  the  pofterior  part  of  the  Head  of  the  Stapes. 

Aftiou  : To  draw  the  Head  of  the  Stapes  obliquely  upwards 
and  backwards,  by  which  die  pofterior  part  of  its  Bale  is  moved 
inwards,  and  the  anterior  part  outwards,  and  the  Membrana 
Tympaui  thereby  put  upon  the  ffretch. 

Labyrinth. 

The  Labyrinth , fo  called  from  its  Sinuofities  and  wind- 
ings, is  !. tutted  attire  inner-part  of  the  Tvmpanum,  and  is 
formed  at  the  Vejribie,  ° ocblea , and  Semicircular  Canals , together 
with  tit t.Canalis  Faikfii  and  'Meatus  Auditorius  Interims, 

The  '/efiitle,  named  from  its  forming  a porch  or  entry  to  the 
Cochlea  arc!  Semicircular  Canals,  isofan  oval  figure,  nearly  of 
the  fize  and  flnp’e  of  a clean  grain  of  Barley,  and  is  fituated  at 
the  inner  fide  of  the  Safe  of  the  Stapes.  . 

There  are- three  contiguous  Cavities  in  the  Veftible,  one  of 
which,  the  Semi-oval,  is  fituated  above;  another,  the  Hemi~ 
fpherical,  below;  and  the  third,-  or  Sulciform,  which  is  the  orifice 
of  the  Aquse'duflus  Veitbuli,  is  placed  behind. 

In  the  Veftible  there  are  fcvcral  Holes  which  communicate  with 
the  neighbourin  r parts,  viz. 

The  Fenejira  Ovalis  fituated  at  the  outfide,  by  which  it  com- 
municates with  the  Tympanum. 

A round  Hole,  fituated  at  tire  fore  and  under-part,  by  which  it 
communicates  with  one  of  the  Canals  of  the  Cochlea. 

Five  Similar  Foramina  behind,  by  which  it  communicates  with 
the  Semicircular  Canals. 

Next  the  Meatus  Auditorius  Interims,  it  has  four  or  five 
Cribriform  Perforations , for  the  tranfmiflion  of  Nerves. 

The  Cochlea  is  fituated  next  the  anterior  extremity  of  the  Os 
Petrofum,  and  at  the  fore-part  of  the  Veftible,  in  fuch  a man- 
ner as  to  have  it;  Bale  towards  the  Jvleatus  Auditorius  Interims, 
and  its  Apex  in  theoppofite  direftion, — or  facing  outwards. 

It  has  two  Canals  or  Gyri,  called  Seal  a,  from  a luppofed  re- 
femblance  to  Stair-cafes,  the  Gyri  or  turns  of  which  are  very 
ciofe  to  each  otner,  and  run  in  a fp:ral  d reflion,  like  the  Shell 
of  a Snail,  from  which  the  par.  has  obtained  its  name. 

The  Cochlea  forms  tvuo  Circumvolutions  or  Tarns  and  a half, 
the  firft  of  which  is  much  larger  and  wider  than  the  other  Turn 
and  a half,  which  become  fuddenly  fmaller. 

The  two  Canals  are  upon  the  fame  level,  the  inner  one  next 
the  Bafe,  and  the  outer  next  the  pont  of  the  Cochlea. 

The  Gyri  go  round  a Nucleus,  Axis,  or  central  Pillar,  which 
is  nearly  horizontal,  and  is  formed  of  tvuo  hollo  vs  Cones , with 
their  points  turned  to  each  other,  the  one  termed  Modiolus , fro® 


52 


its  refemblance  to  the  Spindle  of  a winding  Stair-cafe,  the  other 
Infundibulum,  or  Funnel. 

The  Modiolus  forms  the  inner  and  larger  portion  of  the  central 
Pillar,  and  is  that  Cavity  feen  in  the  under  and  fore-part  of  the 
Meatus  Auditoi  ius  Internus. 

It  lodges  that  branch  of  the  Portio  Mollis  of  the  Seventh  Pair 
of  Nerves,  which  goes  to  the  Cochlea,  and  is  Cribriform,  or  full 
of  fmall  Holes  for  the  paffage  of  the  twigs  of  that  branch. 

The  Modiolus  confilts  of  two  Plates,  with  numerous  Cells 
and  Pajfages  between  them,  and  terminates  in  the  middle  of  the 
fecond  Gyrus  of  the  Cochlea. 

The  Infundibulum  is  an  imperfect  Funnel,  the  Apex  of  which 
is  common  with  that  of  the  Modiolus,  and  the  Bafe  is  covered 
by  the  Apex  of  the  Cochlea,  which  is  termed  Cupola. 

Between  the  Scalae  of  the  Cochlea  there  is  a Partition,  called 
Lamina  Spiralis,  or  Septum  Scala,  the  larger  portion  of  which, 
next  the  Modiolus,  is  formed  of  Bone  : The  remainder,  or  that 
part  next  the  oppofite  fide  of  the  Scalae,  is  Membranous,  and 
termed  by  Valsalva  Zona  Gochlce. — This  drops  out  by  macera- 
tion, fo  as  afterwards  to  leave  only  a partial  Septum. 

The  Offeous  part  of  the  Lamina  Spiralis  is  compofed  of  two 
extremely  thin  Cribriform  Plates,  which  gradually  approach  each 
other  at  their  oppofite  edges,  where  they  are  perforated  by  numer- 
ous Holes. 

The  termination  of  the  Lamina  Spiralis,  and  of  the  Scala 
Tympani,  forms  a Hamulus,  or  fmall  Hook,  which  projedls  into 
the  Infundibulum. 

One  of  the  Canals  or  Scalae  of  the  Cochlea,  opens  into  the  un- 
der and  fore- part 'of  the  Veliible,  and  is  termed  Scala  Vefibuli: 
The  other,  which  is  the  fmaller  of  the  two,  communicates  with 
the  Tympanum  by  the  Feneftra  Rotunda,  and  is  called  Scala 
lympani. 

The  Partition  between  the  two  Gyri  or  Turns  of  the  Cochlea, 
like  the  Ofleous  part  of  the  Lamina  Spiralis,  is  formed  of  two 
Plates,  with  a fmall  Cavity  between  them. 

The  Volute,  or  Spiral  of  the  Cochlea,  begins  below,  runs  for- 
wards, and  then  round,  fo  as  to  form,  as  has  been  already  men- 
tioned, two  Circles  or  Turns  and  a half,  the  direction  of  the 
Gyri  correfponding  with  thole  of  the  Shell  of  a Snail. 

The  Canals  of  the  Cochlea  are  conical,  becoming  gradually 
fmaller  towards  the  Apex,  where  they  communicate  freely  with 
each  oilier,  through  the  medium  of  the  Ini umbbulum. — T his 
communication  is  called  by  Cassebohm,  who  ves  thr  ful.ePc 
Treatif.  upon  the  Ear,  Canalis  ",c alarum  Cot" munis. 

The  Semicircular  Canals  are  three  m numb:  r, — the  Superior  or 
Vertical,— the  Pojlerior  or  Oblique,— and  the  Exterior  or  Hori- 
zontal. 


53 


The  Superior  is  placed  tranverfely,  in  the  upper-part  of  the 
Pars  Petrofo,  with  its  convex  fide  upwards. 

The  Pojierior  is  farther  back  than  the  former  one,  and  is  pa- 
rallel to  the  length  of  the  Pars  Petrofa,  with  the  convex  fide  turned 
backwards. — One  of  its  extremities  is  placed  above,  and  the  other 
below,  the  upper  extremity  joining  with  the  internal  one  of  the 
Vertical  Canal,  by  which  a common  Canal  is  formed. 

The  Exterior  is  lei's  than  the  other  two,  which  are  more  of  an 
equal  fize,  is  placed  next  the  Tympanum,  and  has  its  extremities 
and  curvatures  nearly  , upon  the  iame  plane;— with  the  curve 
placed  backwards. 

Each  of  the  Canals  forms  upwards  of  three-fourths  of  a circle, 
can  admit  the  head  of  a fmall  Pin,  and  has  an  Enlargement, 
Ampulla,  or  Cavitieo  Elliptica,  at  one  end,  the  other  extremity 
being  nearly  of  the  lame  fize  with  the  reft  of  the  Canal. 

The  Orifices  are  only  five  in  number,  two  of  the  Canals  ha- 
ving a common  termination.  OFthefe  Orifices,  three. are  fifua- 
ted  at  the  inlide,  and  two  at  the  outfide  of  the  Vefti.ile,  into  the 
pofterior  part  of  which  they  open. 

In  the  bottom  of  the  Meatus  Auditorious  Internus,  which  is 
fituated  in  the  pofterior  Surface  of  the  Pars  Petrofa,  there  is  a 
large  under,  and  a final  1 • upper  Fojj'ula,  feparated  by  a fharp 
Ridge. 

The  fore-part  of  the  inferior  Foffula  leads  towards  the  Coch- 
lea, and  is  perforated  with  numberlefs  fmall  Holes,  through  which 
branches  of  the  Portio  Mollis  of  the  Seventh  Pair  of  Nerves  pals 
to  the  Cochlea. 

One  Hole  in  the  centre,  larger  than  the  reft,  tranfmits  a branch 
of  that  Nerve  to  the  Infundibulum. — This  Hole,  however,  is 
frequently  enlarged,  in  confequence  of  the  Bone,  which  is  ex- 
tremely thin,  being  broken  while  preparing  it. 

In  the  back-part  of  the  inferior  Foffula,  three  or  four  Cibri- 
form  Holes  appear,  for  the  tranfmiffion  of  branches  of  that  part 
of  the  Portio  Mollis  deftined  for  the  Veltible  and  Semicircular 
Canals. 

In  the-upper  Foffula  of  the  Meatus  Internus,  there  are  t<wo 
Paffages,  one  pofterior  and  fmaller,  tranfmitting  Nerves  into  the 
Elliptical  Cavity  of  the  Veftible. 

The  other,  the  anterior  and  largeft,  is  termed  Canalis  or 
Aqu&duBus  Fallopii , — from  a refemblance  it  bears  to  an  IraFan 
Aqueduct,  and  l’erves  for  a tranfmiffion  of  the  Portio  Dura  of 
the  Seventh  Pair  of  Nerves. 

The  Canal  of  Fallopius  goes  through  the  upper-part  of  the 
Pars  Peirola,  paffes  downwards  and  backwards  between  the 
Foramen  Ovale  and  external  Semicircular  Canal,  and  terminates 
m the  Foramen  Stylo-Maftoideum. 

Vol.  II.  E 2.  J 


In  its  pafTage  through  the  Pars  Petrofa,  it  communicates  with 
the  Foramen  lnriominatum,  lituated  on  the  upper  and  tore-part 
of  the  Procefs. 

In  Children,  the  Labyrinth  is  almoft  as  large  as  in  Adults,  its 
Subftance  complete  and  hard,  "while  the  Bone  which  furrounds  it 
is  foft  and  fpongy  ; on  which  account  it  is  eafily  feparated  from 
the  reft  of  the  Pars  Petrofa. 

The  different  Cavities  and  Paffages  of  the  Labyrinth  are  lined 
with  the  Periofteum,  which  in  the  Veftible  fills  the  Feneftra 
Ovalis,  and  of  confequence  covers  the  Bafe  of  the  Stapes. 

The  Perioftea  of  the  t^o  Canals  of  the  Cochlea  form,  by  their 
union,  the  Membranous  portion  of  the  Lamina  Spiralis,  which, 
together  with  the  Offeous  part,  completes  the  Septum  between  the 
two  Scalae. 

The  Periofteum  of  the  Cochlea  alfo  aftifts  that  of  the  Tym- 
panum, in  forming  the  Membrane  of  the  Feneftra  Rotunda, 
and  which  is  fome, times  called  Membrana  Tympani  Secundarii , 
from  a refemblance  to  the  Membrana  Tympani,  and  from  being, 
like  it,  a lit.le  concave  on  the  outer,  and  convex  on  the  inner 
Surface,  or  where  it  faces  the  Scala  to  which  ii  belongs. 

Befides  the  Periofteum,  the  Veftible,  Cochlea,  and  Semicir- 
cular Canals  contain  a Pulpy  Membrane,  upon  which  the  Portio 
Mollis  is  irregularly  difperfed. 

In  the  Veftible,  the  Pulpy  Membrane  forms  a Sac,  in  ftiape 
vefembling  that  of  the  Offeous  Cavity  which  contains  it,  and 
which  is  deferibed  and  beautifully  deliniated  by  Scarpa. 

When  the  Sac  is  laid  open  upon  the  upper  and  outer-part,  a 
Partition  appears,  of  the  nature  of  the  Sac,  termed  by  Dr. 
Meckel,  Septum  Vejlibuli  Nervofo-membranaceum. 

In  the  Cochlea,  the  Pulpy  Membrane  is  in  contadft  with  the 
Periofteum,  but  can  be  feparated  from  that  Membrane  without 
■ much  difficulty. 

In  the  Semicircular  Canals,  it  is  at  fome  diftar.ee  from  the- 
Periofteum  of  ihefe  Bones,  and  is  confiderably  fmaller,  but,  like 
them,  it  forms  diftinft  Tubes,  which  communicate  with  the 
Veftible.  Like  the  Offeous  Canals  alfo,  the  Membranous  Canals 
form  Ampullae,  or  Elliptic  Cavities  at  one  end. 

The  Arteries  of  the  Labyrinth  aril'e  by  one  or  two  fmall 
branches,  chiefly  from  the  Vertebral  Artery,  and  pafs  through 
the  Ci  ibr  fo.  m Plate,  at  the  bottom  of  the  Meatus  Externus 
which  beiongs  to  the  Labyrinth. 

From  the  Labyrinth  one  or  two  Veins  return,  and  terminate  in 
the  end  of  the  Lateral  Sinus. 

The  Cavity  of  the  Veftible  contains  no  Air,  but  is  conftantly 
filled  with  a Watery  Fluid,  fuppofed  to  be  kcreted  from  the  Ar- 
teries of  the  Periofteum,  and  which  is  found  to  referable  the 
Aqueous  Humour  of  the  Eye. 


5.5 


The  Aqueous  Fluid  fills  the  Veftib'e  and  Seal*  of  the  Coch- 
lea, and  likewife  furrounds  the  Membranous  Semicircular  Ca- 
nals. 

The  Aqua  Labyrinthi  is  confidered  as  a medium  by  which 
founds  are  communicated  from  the  Membrane  filling  the  round 
and  oval  Holes,  and  from  the  Bafe  of  the  Stapes  to  the  Pulpy 
Membrane  placed  in  it. 

The  fuperfluous  part  of  the  Aqua  Labyrinthi  is  fuppofed  by 
Cotun  nius  to  be  carried  off  by  two  fmall  Conical  Duffs,  more 
particularly  deferibed  by  h.m  than  by  fome  preceding  Anato- 
mifts,  who  were  partly  acquainted  with  them,  but  confidered 
them  as  Blood-veffels. 

One  of  the  Aquedufts  of  Cotunnius,  called  Aquaduffus 
Cochlea,  begins  at  the  under-part  of  the  Scala  Tympani,  near 
the  Feneftra  Rotunda,  and  after  palling  through  the  Pars  Petro- 
fa,  is  feen,  in  the  figures  he  gives  of  it,  terminating  by  a wide 
triangular  opening,  upon  the  furface  of  the  Dura  Mater,  be- 
tween the  paffages  of  the  Seventh  and  Eighth  Pair  of  Nerves. 

The  other  Du  ft,  called  Aqueeduffus  Vefibuli,  begins  under  the 
termination  of  the  common  Canal,  in  the  Veilible,  from  which 
it  defeends,  and  terminates  by  a triangular  opening  between  the 
Layers  of  the  Dura  Mater,  behind  the  Meatus  Internus,  and 
half  way  between  the  upper  edge  of  the  Pars  Petrofa  and  Diver- 
ticulum of  the  Internal  jugular  Vein. 

For  a jull  account  of  thefe  Duffs,  and  of  the  other  parts  of  the 
Labyrinth,  fee  a Description  of  thetn  by  Dr.  Meckei,  of  Berlin. 

The  Nerves  of  the  Labyrinth  are  derived  entirely  from  the 
Seventh  Pair. 

The  Auditory  Nerve  is  compofed  of  two  branches,  one  of 
which  is  called  Portio  Dura,  and  is  harder  than  the  other,  ter- 
med Portia  Mollis. 

The  Trunk  of  the  Auditory  Nerve  paffes  into  the  Meatus  Ex- 
ternus,  covered  by  the  mvefting  Membrane  of  the  Brain. 

The  Portio  Dura  goes  through  the  Canalis  Faliopii,  fending 
off,  in  its  paffage,  branches  through  Perforations  in  its  fides,  to 
the  Stapedius  Mufcle  and  Malloid  Cells. 

One  refleffed  branch  paffing  through  the  Foramen  Innomina- 
tum,  in  the  Pars  Petrofa,  forms  a conneftuon  between  the  Por- 
tio Dura  and  the  fecoad  part  of  the  Fifth  Pair. 

Another,  called  Chorda  Lympani,  paffes  aerols  the  Cavity  of 
the  Tympanum,  between  the  inferior  Crus  of  the  Incus  and 
handle  of  the  Mail  us,  and  at  the  mtfide  of  the  Euftachian  Tube, 
to  join  the  Lingual  "ranch  of  the  Fifth  Pair.  In  its  paffage  it 
fuppfes  the  Mufcles  of  the  Malleus,  and  Membranes,  See.  of 
the  Tympanum. 

The  remainder  of  the  Portio  D uais  Tfperfed  upon  the  Face, 

The  Port  19  Mall.'  is  divided  into  two  principal  parts, —one  to 
the  Cochlea,  the  other  to  the  Vchibie, 


56 


The  branches  of  the  Cochlea  pafs  through  the  Cribriform 
Plates  of  the  Modiolus,  to  the  Pulpy  Membrane  lying  in  the 
Sc  alas. 

The  branches  run  between,  and  likewife  on  the  out-fide  of 
the  Partitions  which  devide  the  Cochleae  into  Gyri,  and  the 
Gyrt  into  Scalae,  and  are  large  and  numerous  in  proportion  to 
the  part  they  fupply. 

The  large  ft  and  mod  numerous  of  thefe  branches  are  difperfed 
upon  the  Lamina  Spiralis,  where  they  form  an  intricate  Plexus, 
the  Thieads  of  which  at  e at  fir (l  opaque,  but  are  afterwards  of 
the  colour  of  the  Retina  of  the  Eye. 

The  branches  terminate,  and  appear  alfo  to  meet  upon  that 
part  of  the  Pulpy  Membrane,  which  is  mod  diftant  from  the  Mo- 
diolus. 

Through  the  Cribriform  Plate,  common  to  the  Modiolus  and 
Infundibulum,  the  laft  branches  of  this  portion  of  the  Nerves 
pafs,  to  be  fpread  out  upon  the  Membiane  lying  within  the  In- 
fundibulum.— For  a particular  defcription  oj  that  part  of  the 
Fort  to  Mollis  difributed  to  the  Cochlea  and  oj  the  Cochlea  it- 
felf,  fee  Dr.  Monro’s  Treat  j'e  on  the  Ear. 

Or  that  part  of  the  Portio  Mollis  deftined  for  the  Veftible 
and  oein'cn  cular  Canal one  branch  goes  through  the  pofttrior 
Hole  in  the  upper-part  of  the  Meatus  Internus  ; rhe  reft  pafs 
through  the  holes 'n  the  under  and  back  part  of  the  Meatus, 
already  pointed  out  in  the  defcription  of  that  Paffage. 

After  perforatiu  the  Foramina,  the  Nerves  are  i'een  firft  in 
diftinft  Plexus,  but  become  af  towards  tranfparent,  and  are  loft 
upon  the  Sac  comuned  in  the  Veftible  and  upon  the  Ampulla  of 
the  Membranous  Semicircular  Canals. 

The  Po>  'lo  Mollis  * s the  primary  part  of  the  Organ  of  Hearing, 
to  which  alt  tin.  ...her  ^aris  are  fu  f.rvient,  ai  d may  be  regard- 
ed as  being  of  the  fame  lervice  to  the  Ear,  as  the  Retina  is  to  the 
Eye. 


$1 


OF  THE  MOUTH , Tongue,  AND 
THROAT. 


WITH  THEIR  APPENDAGES, 


MOUTH. 


The  OJfeous  Parts  of  the  mouth  are,— the  OJj'a  Maxillaria  Su- 
per; ora,  the  OJj'a  Palati,  the  Maxilla  Inferior,  and  the  Teeth  j 
—all  of  which  have  been  already  defcribed. 

The  Sojt  Parts  of  the  Mouth  confift  of  the  Lips  and  Cheeks , 
the  Gums , the  Palate,  the  Velum  Palati the  Uvula,  the  Tongue, 
the  Membrane  lining  the  Mouth  and  the  Salivary  Glands. 

The  Lips  and  Cheeks  are  principally  compofed  ofMulcles,  are 
covered  on  the  outfide  by  the  common  Integuments,  and  lined 
within  by  the  Membrane  of  the  Mouth,  under  which  there  are 
numerous  Mucous  Glands,  which  obtain  their  names  from  their 
fituations. 

The  intervening  fpace  between  the  Mafleter  and  Buccinator 
Mufcles  is  occupied  by  a large  quantity  of  Fat,  which  gives  form 
to  the  Face. 

The  Membrane  of  the  Mouth  is  covered  with  fine  Villi ; but 
thefe  are  mod  conspicuous  upon  the  edges  of  the  Lips,  as  may 
be  readily  feen  after  a fine  injection,  or  after  macerating  the  parts 
till  the  Cuticle  can  be  feparated. 

From  the  edges  of  the  Lips,  the  Common  Integuments  (now 
become  extremely  thin)  are  converted  into  the  Membrane  which 
is  continued  into  the  Cavity  of  the  Mouth,  and  which,  oppofite 
to  the  Dentes  Incifores  of  the  Upper  and  Under  Jaws,  forms  a 
ftnall  Doubling  or  Franum,  which  fixes  the  Lips  more  firmly  to 
the  Jaws. 

The  Lips  are  ferviceable  in  the  general  purpofes  of  Speaking, 
Eating,  Drinking,  See. 

The  Gums  cover  the  tides  of  the  Alveolar  Border  of  both  Jaws, 
pafs  in  between  the  different  Teeth,  and  funounu  and  adhere 
firmly  to  the  Collar  of  each. 

The  Subltanceof  the  Gums  is  of  a denfe  nature,  veiy  Vafcu- 
lar,  and  the  Veffels  united  by  a compact  Cellular  Subftance. 


58 


They  may  be  fnid  to  confift  of  the  Common  Membrane  of  the 
Mouth  and  the  Periofteum  of  the  Jaws  intimately  conneffed. 

They  feme  as  a covering  to  the  Jaws  and  affift  in  the  feeuiity 
of  the  Teeth, 

The  Arteries  of  the  Lips,  Cheeks,  and  Gums,  are  from  the 
Facial,  Temporal,  and  Internal  Maxillarie?,  which  are  derived 
from  the  External  Carotids. 

The  Veins  go  chiefly  to  the  External,  -and  partly  to  the  Inter- 
nal Jugulars. 

The  Nerves  rome  from  the  firll  and  fecond  branches  of  the 
Fifth  Pair,  and  nll'c  from  the  Port'o  Dura  of  the  Seventh  Pair. 

* he  Palate  ;s  divided  into  the  Palatum  Dure  and  Palatum 
Malle.  The  forrner  is  compofea  of  the  Palate-plates  of  the  Up- 
per Jaw,  and  is  covered  by  the  Periofteum  and  common  Mem- 
brane ot  tile  Mouth,  which  prevent  the  Bones  from  being  in- 
jured. 

The  Membrane  which  covers  the  Bones  of  the  Palate  forms 
numerous  Ruga?,  which  aflift  in  the  divifion  of  the  Food. 

It  is  nearly  of  the. fame  ltru£Iure  with  that  of  the  Gums,  but 
perforated  by  the  Dufts  of  the  Palatine  Glands,  for  th:  excretion 
of  Mucus,  which  ferves  to  lubricate  the  Palate,  and  nffilts  in 
thflblving  the  Food. 

The  Palatum  Molls,  Velum  Pendulum  Palati , or  Soft  Palate, 
is  that  pai  t which  depends  from  the  poflerior  edge  of  the  Ofl'a 
Pala'i,  and  from  the  Pterygoid  Procefl’es  of  the  Sphenoid  Bone, 
and  forms  a Partition  between  the  Nofe  and  Mouth. 

It  is  compofed  of  the  Membranes  which  line  the  Nofe  and 
Mot  th,  at  id  of  the  expanfions  of  the  Circumflex  and  Levator 
Palati  Mufcles,  and  numerous  Mucous  Glands  which  fei  ve  to 
lubricate  he  Mouth  and  Throat,  anti  facilitate  deglutition. 

The  Palatum  Molle  conducts  the  Fluids  of  the  Nofe  into  the 
Mouth,  and  afls  like  a Valve  in  preventing  what  we  fwallow  from 
pafiing  into  the  nofe. 

In  the  middle  of  the  poflerior  edge  of  the  Velum  Palati,  the 
Uvula  or  Pap  of  the  Throat,  takes  Its  orgin,  and  hangs  pen- 
dulous, from  the  Velum  over  the  root  of  the  Tongue. 

It  is  of  a Conical  farm,  is  covered  by  the  Membrane  of  the 
Mouth,  and  has  a fmnll  Mufcle  wilhin  it,  by  which  it  is  eleva- 
ted and  ihortened , — its  other  motions  depending  upon  the  Muf- 
cle ; of  the  Palate. 

The  ufe  cf  the  Uvula  in  Speaking  and  in  Deglutition,  is  evi- 
dent from  the  inconveniencies  which  refult  from  its  being  deftroy- 
ed  by  dileafe. 

The  Arteries  of  the  Palate,  See,  come  from  the  Facial,  and 
Internal  Maxillary. 

The  Veins  go  the  External  and  Internal  Jugulars.' 

The  Nerves  are  chiefly  from  the  l'econd  of  the  Fifth,  with 
, fome  twigs  from  the  Eighth  Pair. 


59 


Tongue. 

The  Tongue  is  of  an  Oval  form,  and  is  divided  into  Safe , 
Body  and  Apex. 

The  Safe,  or  pofteror  part  of  the  Tongue,  isconneCfed  to  the 
Os  Hyoides,  and  by  the  medium  of  this,  to  the  adjacent  Bones 
and  Mufcles. 

The  Body,  or  middle  part  of  the  Tongue,  terminates  anteri- 
orly in  the  loofe  moveable  point. 

On  theDorfum  or  upper  Surface,  there  is  a Lbtea  Mediana,  or 
middle  Groove,  running  longitudinally,  and  dividing  it  into  two 
lateral  convexities. 

The  inferior  Surface,  which  reaches  only  from  the  middle  of 
the  Tongue  to  the  po:nt,  is  connected  to  the  parts  below  it  by  the 
Sublingual  Ligament,  or  Franum  Lingua,  which  is  a doubling 
of  the  Skin,  or  lining  of  the  Mouth. 

The  (ides  of  the  Tongue  are  fixed  to  the  Lower  Jaw  and  Sty- 
loid Procefies,  and  pans  adjacent,  by  Membranous  Ligaments. 

The  Ton.  ue  is  chiefly  compofed  of  the  Fibres  of  the  Mufcles 
which  fei  ve  for  its  motions. — Thefe  Fibres  are  difpofed  in  vari- 
ous directions,  and  intermixed  with  a Medullary  Fat. 

The  upper  and  lateral  pans  of  the  Tongue  are  compofed  of  the 
Stylo-Glofli. — Its  middle  portion,  between  the  two  former  Muf- 
cles, is  formed  of  the  Linguales. — The  lower  part  is  chiefly 
formed  of  the  Genio-Gloffi  ; — and  behind,  the  Stylo-Glofli  en- 
ter into  its  compofition. 

The  Tongue  is  covered  by  a continuation  of  the  common  In- 
teguments, which  are  preferved  foft  and  moilt  by  the  Saliva. 

The  Cuticle  forms  Vaginae  for  receiving  the  Subftances  called 
Papilla. 

The  Corpus  Mucofum  of  the  Tongue  is  thicker  than  in  other 
parts  of  the  Body,  but  more  moift. 

The  third  covering  of  the  Tongue,  the  Cutis  Vera,  is  remark- 
ably Nervous. — The  Papillae,  which  take  their  origin  from  it  are 
very  Vafcular,  efpecially  near  the  Apex  of  the  Tongue,  but  are 
awantingon  its  under  furface. 

The  Papilla  are  divided  into  three  kinds,  the  Maxima,  Media, 
and  Minima. 

The  fii  It  clafs,  called  Papilla  Maxima,  Lenticulares,  or 
Lapilata,  are  by  much  the  lar  eft,  and  of  a Lenticular  form, 
having  round  Heads  and  fhort  Stems. 

They  are  placed  at  the  Bafe  of  the  Tongue,  in  fupcrficial  Fol'- 
fulae,  and  are  diloerfe  : in  inch  a manner  as  to  form  an  angle 
with  its  point  backwards. 

They  are  Glands  of  To  Saliv;  ry  kind,  and  have  each  of  them 
a fmall  Perforation  in  the  middle  of  its  convex  SuT^ce,  for  the 
excretion  of  Mucus. 


GO 


Befides  the  Paplllse  Capitatge,  there  are  numerous  Mucoy , 
Follicles,  which  cover  the  greater  part  of  the  Surface  of  the  root 
of  the  Tongue. 

At  the  root  of  the  Tongue,  and  behind  the  angle  formed  by 
the  Papillae  Maximse,  there  is  a Hole,  called  Fo>  amen  Case  uni  of 
Morgagni,  by  whom  it  was  firft  deferihed. 

It  penetrates  only  a fmall  way  into  the  Subftanceof  the  Tongue, 
and  receives  the  Mouths  of  feveral  Excretory  Dufts  which  termi- 
nate in  it. 

The  fecond  clafs  called  Papilla  Mediae,  or  Semi -lenticular es , 
are  much  fmaller  than  the  former,  and  aie  fcattered  over  the  up- 
per Suilace  of  the  Tongue,  at  fome  diftance  from  each  other. 

They  are  of  a Cyndrical  form,  and  terminated  by  a round  ex- 
tremity. 

The  third  clafs,  termed  Papilla  Minima,  or  Conica,  cr  Vil- 
lofa,  are  by  much  the  moft  numerous,  but  very  minute.  They 
occu;  y almoft  the  whole  upper  Surface  of  the  Tongue,  but  are 
moft  abundant  towards  the  Apex,  where  the  fenl'atipn  of  Tafte  is 
moft  acute. 

This  and  the  fecond  clafs  have  been  fuppofed  to  be  formed 
chiefly  of  the  extremities  of  Nerves,  and  to  conftitute  the  real  Or- 
gan of  Tafte  ; though  other  parts,  as  the  Palate,  and  even  the 
Pharynx  and  Efophagus,  poflefs  the  faculty  of  Talte  in  a certain 
degree. 

The  principal  Blood-veflels  of  the  Tongue  are  large  in  propor- 
tion to  the  fize  of  that  Organ. 

They  are  called  Linguales,  or  Ranina,  on  account  of  the  dark- 
coloured  branches  which  appear  under  the  Tongue. 

The  Arteries,  wh  ch  are  branches  of  the  External  Carotids,  are 
not  found  to  communicate  fo  freely  on  the  oppofile  fides  of  the 
Tongue,  as  they  do  in  other  parts  of  the  Body. 

The  Veins  open  chiefly  into  the  External  Jugulars. 

The  Nerves  like  the  Arteries,  are  large  and  numerous,  and 
have  little  connexion  on  the  oppofie  Tides. 

They  come  from  the  F fth.  Eighth,  and  N. nth  Pair: . 

The  firft  let  fupply  the  pans  next  the  point  of  the  Tongue, 
and  are  therefore  confidered  as  being  principally  concerned  in  con- 
veying the  fenfation  of  Tafte. 

The  fecond  let  fupply  the  root  and  the  third  the  middle  of  the 
Tongue,  and  are  chiefly  difperfed  upon  its  Mufcles. — There  is 
a confidera'de  intermixture,  however,  between  the  three  fets  on 
the  fame  fide. 

Befides  being  the  principal  Organ  of  Tafte,  the  Tongue  is  the 
chief  inftrument  of  Speech,  and  of  the  ai t, eolation  of  the  Voice, 
—It  alfo  aflifts  in  Manducation,  Deglutition,  Spitting,’  Suck- 
ing, &c. 

The  Salivary  Glands  ronfift  of  three  large  Glands  on  eacn 
fide  of  the  Face,  viz. — the  Parotid,  the  Submaxillary,  and  the 


61 


Sublingual ; — befides  many  fmall  Glands,  named  from  the  parts 
to  which  they  belong. 

They  are  of  a yellowifh  colour,  and  irregular  on  their  Surface, 
being  of  the  Conglomerate  kind. 

The  Parotid  Gland,  which  is  the  larged  of  the  Salivary  Glands, 
is  named  from  its  fituation  near  the  Ear. 

It  occupies  the  whole  fpace  between  the  Ear,  Maftoid  Procefs, 
and  the  angle  of  the  Lower  Jaw. 

It  extends  fuperiorly  to  the  Zygoma,  and  anteriorly  to  the 
Mafleter  Mufcle,  part  of  which  it  covers. 

The  under  end  of  it  lies  contiguous  to  the  Submaxillary  Gland. 

From  the  different  parts  of  the  Gland,  numerous  fmall  branch- 
es arife,  which  join  together  to  form  a large  Duff,  fometimes 
called  StenS’s  Salivary  Duel,  or  Ductus  Superior,  which  paffes 
from  the  upper  and  fore-part  of  the  Gland. 

The  Parotid  Duff  is  of  a white  colour  and  large  fize,  but, 
from  the  thicknefs  of  its  Coats,  the  Cavity  is  fmall  in  propor- 
tion to  the  outfide  of  the  Duff. 

It  paffes  anter  orly,  in  a tranfverfe  direffion,  over  the  Tendon 
of  the  Maffeter  Mufcle,  by  which  it  is  free  from  compreffion,  and 
defeends  a little  to  perforate  the  Buccinator  Mufcle,  oppofite  to 
the  fecond  or  third  Dens  Molaris  of  the  Upper  Jaw. 

In  crofTmg  the  Maffeter  Mufcle,  it  receives  fometimes  one, 
fometimes  two  minute  Duffs,  from  an  equal  number  of  fmall 
Glands,  called  by  Haller,  Glandules  AcceJJbria;. 

The  Inferior  Maxillary,  or  Submaxillary  Gland,  is  fmaller  and 
rounder  than  the  Parotid,  and  is  fituated  on  the  infide  of  the  an- 
gle of  the  Lower  Jaw,  between  it  and  the  Tendon  of  the  Digaf- 
tric  Mufcle. 

From  the  upper  and  fore-part  of  this  Gland,  aDuffarifes, 
called  by  fome  Authors  Duftus  Whartonii,  or  Ductus  Inferior , 
which  is  much  thinner  in  fubftance  than  the  former  Duff,  but 
longer. 

It  paffes  forwards  between  the  Mylo-Hyoideus  and  Genio- 
Glofl'us  Mufcles,  along  the  under  and  inner  edge  of  the  Sub- 
lingual Gland,  to  the  fide  of  the  Fraenum  Linguae,  and  terminates 
behind  the  Dentes  Incifores,  by  a fmall  orifice,  in  form  of  a Pa. 
pilia. 

The  Sublingual  Gland  is  fmaller  and  fofter  than  the  Submaxil- 
lary,  and  is  flat,  and  of  an  aval  form. 

It  is  fituated  under  the  anterior  portion  of  the  Tongue,  above 
the  Duff  of  the  inferior  Maxillary  Gland  near  the  Lower  Jaw, 
between  the  Myio-Hyoides  and  Genio-hyogloffus  Mufcles,  the 
former  of  which  l'uftains  it. 

Its  extremities  are  turned  forwards  and  backwards,  and  the 
edges  obliquely  inwards  and  outwards. 

It  is  covered  by  a continuation  of  the  Skin  of  the  under  fide  of 
the  Tongue,  which  fixes  the  Gland  in  itsp!ace. 

Vol.  Jf.  F 


612 


It  opens  by  feveral  orifices  arranged  in  a line  near  the  Gums,  a 
little  to  the  outfide  of  the  Fraenum. 

In  many  Quadrupeds,  there  is  a diftinfl  dud!  belonging  to  this 
Gland,  like  that  of  the  Submaxillary 

Sometimes  this  Gland  fends  off  a Branch  which  communicates 
with  that  of  the  Submaxillary,  but  generally  it  is  otherwife. 

The  ftnaller  Glands  of  the  Mouth  are  in  great  nnmbers,  lying 
between  the  inner  lining  of  the  Mouth  and  its  Mufclcs,  and  de- 
riving their  names  from  their  fituations. 

They  are  fmail  fimple  Glands,  each  fending  a duff,  which 
perforates  the  Skin  of  the  Mouth,  and  opens  into  its  Cavity. — 
They  confift  of — 

The  Bucca.les,  which  are  placed  all  over  the  Cheek,  but  moft 
plentifully  near  the  termination  of  the  Parotid  Dudt ; 

The  Labiales,  lying  on  the  infide  of  the  Lips  j 

The  Palatine,  upon  the  Palate  ; and 

The  Linguales,  at  the  root  of  the  Tongue. 

The  Arteries  of  the  Salivary  Glands  are  from  different  Branch- 
es of  the  External  Carotids. 

The  Parotid  is  fupplied  from  the  Temporal , the  Inferior  Max- 
illary from  the  Facial,  and  the  Sublingual  from  the  Lingual  Ar- 
tery. 

The  Veins  of  thefe  Glands  go  to  the  External  Jugulars. 

Their  Nerves  are  chiefly  from  the  third  part  of  the  Fifth, 
and  from  the  P«rtio  Dura  of  the  Seventh  Pair. 

The  Salivary  Glands  ferre  for  the  fecretion  of  the  Saliva, 
which  they  pour  out  in  large  quantity,  and  which  is  promoted  by 
the  motion  of  the  Lower  jaw. — The  Saliva  afiifts  in  the  folution 
of  the  food  in  the  Mouth,  in  lubricating  the  throat  for  its  paffage 
downwards,  and  in  the  digeftion  of  it  in  the  Stomach. 


THROAT. 


The  Throat  confifh  of  the  Arches  of  the  Palate , of  the  Pharynx 
and  Larynx,  with  the  Mufcles,  Vejfels,  Nerves , &c.  which  fur- 
round  them. 

The  Arches  of  the  Palate  are  two  in  number,  in  each  fide  of 
the  Throat,  one  of  which  is  termed  the  Anterior , the  other  the 
Poflerior. 

They  are  formed  of  a Doubling  of  the  Skin,  with  a few  feat- 
hered Mufcular  Fibres. 

The  Anterior  arifes  from  the  middle  of  the  Velum  Palati,  at  the 
fide  of  the  Uvula,  and  is  fixed  to  the  edge  of  the  Bafe  of  the 
Tongue.  t 


T'he  Pojlerior  has  its  origin  likewife  from  the  fide  of  the  Uvu- 
la, and  patfes  downwards,  to  be  inserted  into  the  fide  of  the 
Pharynx. 

The  Anterior  Arch  contains  the  Circumflex  Mufcle  of  the  Pa- 
late, and,  with  its  fellow  on  the  oppofite  fide,  forms  the  open- 
ing into  theThioat,  called  Ijihmus  Foucium. 

The  Pol'terior  Arch  has  within  it  the  Levator  Mufcle  of  die  Pa- 
late. 

Between  the  Anterior  and  Pofterior  Arches,  and  clofe  by  th-s 
fides  of  the  Bale  of  the  Tongue,  the  Amygdala,  Tonfils , or  Al- 
monds of  the  Ears  are  fitv.ated.  - 

They  are  of  a reddifh  coLur,  of  the  figure  of  Almonds,  full 
of  Cells  which  communicate  with  each  other,  and  have  large  ir- 
regular openings,  which  convey  the  Mucus  into  the  Throat,  the 
discharge  of  which  is  promoted  by  the  motion  of  the  furrouiid'- 
ing  parts. 

. Pharynx. 

The  Pharynx,  fo  called  from  its  conveying  Food  to  the  Sto- 
re tch,  and  Air  to  the  Lungs,  is  a large  Mufcular  Bag,  in  form 
of  an  irregular  Funnel,  with  the  Tube  called  Efophdgus  defend- 
ing from  it,  and  forming  the  under  end  of  that  Funnel. 

It  is  bounded  above  by  the  Cuneiform  Procefs  of  the  Occipital 
Bone,  the  Pterygoid  Procelfes  of  the  Sphenoid  Bone,  and  back- 
part  of  the  Jaws,  with  all  of  which  it  is  intimately  connefted. 

The  anterior  margins  of  its  Flelhy  parts  are  connefted  to  the 
edges  of  the  Larynx,  and  its  fides  are  covered  by  the  great  Blood- 
veflels  of  the  Neck. 

The  fore-part  of  the  Pharynx  is  formed  by  a Membrane  com- 
mon to  it  and  to  the  back-part  of  the  Larynx. 

Behind,  it  lies  flat  upon  the  Cervical  Vertebrae,  and  upon  the 
Mufcles  which  cover  the  fore-parts  of  the  fides  of  thefe  Verte- 
brae. 

It  has  feveral  Openings  by  which  it  communicates  with  neigh- 
bouring Cavities. 

Two  of  thefe  lead  upwards  and  forwards  by  the  pofferior 
Nares  into  the  Nofe  ; — two  go  laterally  by  the  Euftachian  Tubes 
to  the  Ears; — one  pafles  forwards  through  the  large  opening, 
termed  Fauces,  or  Top  of  the  Throat,  to  the  Mouth  one  goes 
downwards  and  forwards,  through  the  Larynx  and  Trachea,  to 
the  Lungs  : — and  another  direftly  downwards  by  the  Efophagvis 
to  the  Stomach. 

The  Pharynx  is  fu-rrounded  by  a loofe  Cellular  Subftance,  and 
confifts  of  different  Layers  of  Mufcles,  called  Conjlriftores  Pha- 
ryngis,  which  have  been  already  defcribed. 

On  the  inner  fide,  it  is  lined  by  the  continuation  of  the  Mem- 
brane of  the  Mouth,  which  is  perforated  by  the  Duffs  of  nume- 
rous Glands,  for  the  fecxetion  of  Mucus, 


64 


The  lower  end  of  the  Pharynx,  oppofite  to  the  under  edge  of 
the  Cricoid  Cartilage,  defcribes  a complete  Circle,  which 
forms  the  beginning  of  the  Efophagus. 

The  Pharynx  is  fupplied  with  Blood  by  the  Pharyngeal 
Branches,  which  come  direftly  or  indireftly  from  the  External 
Carotids.  It  returns  its  blood  to  both  Jugular  Veint.— Its  nerves 
are  from  the  Eighth  Pair.  — - 

The  Ufe  of  the  Pharynx  is, — to  receive  the  Aliments  from  the 
Mouth,  and  by  the  aClion  of  its  Mufcles  to  convey  them  to  the 
Eiophagus.  It  mufti ikewifeaflt ft  in  the  modification  of  the  Voice. 

Larynx. 

The  Larynx,  Co  called  from  its  being  the  principal  Organ  of 
Voice,  is  fituated  at  the  upper  and  fore-part  of  the  Neck  imme- 
diately under  the  Os  Hyoides,  which  is  placed  at  the  root  of  the 
Tongue. 

It  is  compofed  of  Cartilages  and  Mufcles,  Ligaments,  Mem- 
branes, and  Mucous  Glands;  and  is  connected  above  to  the 
Tongue  and  Os  Hyoides,  and  behind  to  the  Pharynx. 

The  Cartilages  of  the  Larynx  are  generally  contidered  as  being 
five  in  number,  though,  belides  thefe,  fome  choofe  to  enumerate 
fmall  Projections  which  are  connected  with  them. 

The  Five  Cartilages  are,— the  Thyroid , the  Cricoid , the  Two 
Arytenoid , and  the  Epiglottis. 

The  Thyroid,  Scutiform,  or  Sbield-like  Cartilage,  is  placed  at 
the  upper  and  fore-part  of  the  Larynx,  and  is  the  larged:  of  the 
whole. 

When  fpread  out,  it  is  of  an  oblong  fhape,  but,  in  the  natu- 
ral fituation,  it  confids  of  two  lateral  Wings  or  Portions,  of  a 
quadrangular  form,  uniting  before  in  a longitudinal  angle, 
which  can  be  readily  felt  in  the  fore-part  of  the  Throat,  and 
which,  from  its  projecting  more  in  Men  than  in  Women,  has 
obtained  the  name  of  Pomum  Ad  ami. 

The  uppet  part  of  the  angle  is  formed  into  a Notch,  from 
which,  and  from  the  upper  edge  of  the  Cartilage  in  general,  a 
broad  Ligament  afcends,  to  fix  it  to  the  under-part  ot  the  Os 
Hyoides. 

From  the  poderior  coi  ners  four  proceffes  projeCt,  called  Cornua, 
two  of  which  termed  Superior,  are  long,  and  alcend  to  be  joined 
by  round  Ligaments  to  the  extremities  of  the  Cornua  of  the  Os 
Hyoides. 

In  the  middle  of  thefe  Ligaments,  one  or  two  fmall  Cartilagi- 
nous, or  even  Offeous  Subdances,  are  frequently  found. 

The  other  two  Cornua,  called  Infeiior,  'are  fhorter  than  tne 
Superior,  and  curved  backwards,  to  be  fixed  to  the  Tides  of  the 
Cricoid  Cartilage. 

The  Thyroid  Cartilage  ferves  for  the  protection  of  the  other 
Cartilages,  and,  along  with  the  Os  Hyoides,  preferves  the  Pal-, 
•■age  open,  for  the  tranfmiffion  of  the  Food  to  the  Stomach. 


bo 

The  Cricoid,  or  Annular,  or  Ring-like,  Cartilage,  is  placed 
below,  and  likewife  behind  the  Thyroid,  and  like  it,  may  be 
readily  felt  in  the  fore-part  of  the  Throat. 

It  is  narrow  before,  where  it  lies  under  the  Thyroid  Cartilage, 
and  thick,  broad  and  ftrong  polferiorly,  where  it  is  placed  be- 
hind that  Cartilage. 

Its  Pofterior  Surface  is  divided  by  a Ridge  into  two  lateral  Ca- 
vities, for  the  reception  of  the  pofterior  Cricoarytenoid  Muf- 
cles. 

Its  under  edge  is  horizontal,  and  fixed  to  the  beginning,  or 
firft  Cartilage  of  the  Trachea. 

The  upper  edge  Hants  conliderably,  and  has  its  anterior  nar- 
row part  fixed  to  the  under  edge  of  the  Thyroid  Cartilage. 

It  has  four  fmall  Articular  Surfaces,  with  diftinft  Capfular 
Ligaments,  of  which  two  are  placed  above,  for  he  articulation 
of  the  Arytenoid  Cartilages,  and  two  at  the  under  and  lateral 
parts,  for  the  connexion  of  the  iuferior  Cornua  of  the  Thyroid 
Cartilage.  - 

The  Cricoid  Cartilage  forms  part  of  the  general  Tube  of  the 
Trachea,  conftitutes  the  Bale  of  the  Larynx,  and  gives  a firm 
fupport  to  the  Arytenoid  Cartilages. 

The  two  Arytenoid  Cartilages,  named  from  a fuppofed  refern- 
blance  to  an  Ewer,  or  Drinking- cup  of  the  Ancients,  are  much 
fmalier  than  the  other  Cartilages,  and  are  placed  upon  the  up- 
per pofte  ior,  and  lateral  parts  of  the  Ciicoid  Cartilage,  at  a 
fmall  di fiance  front  each  other. 

They  are  of  a triangular  form,  and  a little  twifted,  and  are 
bent  back,  fo  as  to  have  a broad  concave  Surface  belt  nd. 

Their  upper  extremities  aie  turned  towards  each  other,  and  are 
confidered  by  feme  Authors  as  diftindl  Cartilages. 

Their  Baies  are  broad  and  hollow,  where  they  are  articulated 
by  Capfular  Ligaments  with  the  Cricoid  Cartilage,  upon  which 
they  are  moved  in  different  directions,  by  the  aftion  of  vari- 
ous Myfcles. 

They  are  connefled  to  each  other,  and  to  the  adjacent  Cartila- 
ges, by  different  Mul'cles  and  Ligaments. 

The  Arytenoid  Cartilages  form  a part  of  the  opening  called 
Glottis,  and  give  attachment  ,o  its  Ligaments. 

The  Epiglottis,  obtaining  its  name  from  its  fituation  above,  the 
Glottis,  is  of  an  oval  form  when  furrounded  by  its  Ligaments 
and  Membranes,  but,  when  divefted  of  thelb,  it  is  found  to  be 
narrow  below,  broad  above,  and  rounded  at  its  upper  extre- 
mity. 

It  is  convex  towards  the  Tongue,  and  concave  towards  the 
Glottis,  with  its  point  reflected  a little  forwards. 

It  is  placed  behind  the  upper  part  of  the  Thyroid  Cartilage,  is 
fituated  obliquely  over  the  Glottis,  and  may  be  fesn  and  examin- 
ed by  preffing  down  the  root  of  the  Tongue, 

Yoc..  U.  F 2 


66 


Its  under  end  is  fixed  by  a broad  and  fiiort  Ligament  to  the  mid- 
dle Notch  of  the  T hyroid  Cartilage,  and  by  two  lateral  Liga- 
ments to  the  whole  length  of  the  Arytenoid  Cartilages. 

It  is  fixed  to  the  roots  of  the  Os  Hyoides  and  Tongue  by  ano- 
ther Ligament,  which  is  a doubling  of  the  inner  Membrane 
running  along  the  middle  of  its  anterior  Surface,  and  forming  the 
Lranum  Epiglottidis. 

It  is  very  elaftic,  and  is  much  more  pliable  than  the  other  Car- 
tilages, being  of  a Cartilago  ligamentous  nature. 

It  is  found  to  have  a number  of  Fiffures,  in  which  Lacuna  are 
placed,  and  to  be  perforated  by  numerous  Foramina , which  are 
the  Mouths  of  fo  many  Mucous  Follicles,  and  which  are  in  a 
great  meafure  concealed  by  the  Membrane  which  covers  it. 

It  breaks  the  current  of  the  Air  coming  from  the  Mouth  and 
Nofe,  and  prevents  it  from  rufhing  too  forcibly  into  the  Cavity 
of  the  Lungs. — Preffed  and  drawn  down  by  the  Tongue  and 
by  fmal!  Mufcles,  it  defends  the  Glottis,  and  flints  it  com- 
pletely in  the  time  of  fwallowing. — After  theaffion  of  fwallow- 
tng,  it  is  railed  bv  its  own  elafticity,  and  by  the  root  of  the 
Ton  gue  to  which  it  is  fixed,  returning  to  its  former  p’  fition. 

Ligaments  of  the  Glottis. — From  the  fore-part  of  the  body  of 
Each  of  the  Arytenoid  Cartilages,  a Ligamentous  Cord  pafles  hori- 
zontally forwards,  to  be  fixed  by  its  other  extremity  to  the  iniide 
of  the  anterior  angle  of  the  Thyroid  Cartilage. 

The  opening  formed  between  tbel'e  Ligaments  is  called  Glottis, 
from  the  Greek  : It  is  alfo  called  Mouth  of  the  Larynx,  and 
Rima  Glotlidis,  and  is  of  a triangular  figure,  the  Ligaments 
being  at  a greater  difiance  behind  than  at  their  anterior  extre- 
mity. 

Under  thefe.two  Ligaments  there  are  two  others,  larger  and 
more  diftinft  than  the  former  and  whicn  are  commonly  confidered 
as  the  proper  Ligaments  of  the  Glottis.  They  arife  from  the  Bale 
of  tnc  Arytenoid  Cartilages,  and  run  in  the  fame  direflion  with 
the  former,  to  be  fixed  alfo  to  the  Thyroid  Cartilage. 

In  the  Interftice  of  the  Superior  and  Inferior  Ligaments,  on 
each  fide  there  is  a Fifure,  which  leads  to  a fmall  Membranous 
Cavity  or  Depreftion,  with  its  bottom  turned  outwards. 

Thcfe  are  the  Ventricles  of  the  Larynx  of  Galen. — They  arc 
chiefly  formed  by  the  inner  Membrane  of  the  Larynx. 

They  differ  in  fize  in  different  people,  have  Mucous  Follicles 
opening  into  them,  and  are  found  to  be  ferviceable  in  the  modula- 
tion of  the  Voice. 

On  the  anterior  Surface  of  the  Arytenoid  Cartilages,  there  is  a 
fmall  Depreffion  fi  1 led  by  a Glandular  Body,  which  not  only 
covers  the  fore-part  of  thefe  Cartilages,  but  is  continued  over  the 
poflerior  extremity  of  he  Ligaments  of  the  Glottis. 

The  Arytenoid  Glands  are  larger  in  fome  fubjeffs  than  in  others. 
They  were  difeovered,  and  are  particularly  deferibed  and  deline- 
ate, by  Morgagni. 


67 


The  Ligaments  which  connect  the  Epiglottis  to  the  Notch  of 
the  Thyroid  Cartilage,  and  to  the  under  fide  of  the  Os  Hyoules, 
and  one  which  ties  theBafe  of  the  Os  Hyoides,  form  a triangular 
J pace , which  is  alio  occupied  by  Cellular  Sublfance  and  by  Mu- 
cous Glands. 

The  Cavity  of  the  Larynx  is  lined  by  a membrane  which  is 
extremely  irritable,  and  is  every  where  perforated  by  the  Mouths 
of  fmall  Mucous  Glands,  for  the  purpofe  of  moiftening  it. 

The  Larynx  has  a number  of  Mulcles,  for  its  different  mo- 
tions; all  of  which  have  been  already  defcribed. 

Tile  Arteries  of  the  Larynx  are  the  two  fuperior  Laryngeals, 
which  come  from  the  External  Carotids,  and  the  two  inferior 
Laryngeals,  which  are  fen t off  from  the  Subclavian  Arteries. 

The  Veins  return  to  the  External  Jugulars. 

The  Ner-ves  are  chiefly  the  fuperior  and  inferior  Laryngeals, 
which  are  branches  of  the  Eighth  Pair. 

The  Larynx  ferves  the  purpofe  of  Refpiration,  forms  and  mo- 
dulates the  Voice,  and  is  alfo  ufeful  in  Deglutition. 

It  is  the  principal  Organ  of  Voice;— for,  if  a hole  be  made  in 
the  Trachea,  and  the  paflage  of  the  Larynx  flopped,  the  Air 
efcapes  by  that  opening  without  producing  Voice. 

Voice  is  formed  by  the  Air,  in  its  paflage  through  the  Glottis, 
ailing  upon  the  Ligaments  of  the  Glottis  and  Cartilages  of  the 
Larynx  and  Trachea,  and  thus  producing  a Tremour; — and  is 
different  in  different  perfons,  according  to  the  Form  and  Structure 
of  the  Larynx. 

The  ftrength  of  Voice  is  in  proportion  to  the  quantity  of  Air 
expired,  and  the  narrownefs  of  the  Glottis. 

A Tone  is  acute  in  proportion  to  the  tenfion  of  the  parts  of- 
the  Laiynff  and  Trachea  in  general,  and  of  the  Ligaments  of  the 
Glottis  in  particular. 

A Tone  is  grave  in  proportion  to  the  reverfe  of  the  above. 

Speech  is  performed  chiefly  by  the  different  parts  of  the  Mouth, 
affifted  by  the  Cavity  of  the  Nofe, — the  Larynx  moving  only  in 
a fmall  degree. 

When  the  Air  pafles  through  the  Larynx  without  producing  a 
Tremour  it  occaftons  a Whifper. 

When  a perfon  fpeak  during  infpiration,  the  voice  is  thereby 
very  materially  altered  ; and,  by  practice,  may  be  made  to  ap- 
pear as  coming  from  other  places  than  the  mouth  cf  the  fpeaker  ; 
as  ts  the  cafe  with  thole  who  cal)  themfelves  Ventriloquijis. 


OF  THE  THORAX. 


The  Thorax,  or  Breajl,  extends  from  the  neck  to  the  Dia- 
phragm, and  is  divided  into  External  and  Internal  Parts. 

EXTERNAL  PARTS  OF  THE  THORAX. 

The  External  Parts  of  the  Thorax,  befides  the  common  In- 
teguments and  Mammas,  are, 

The  Mufcles,  confiding  of  the  Peclorales,  Subclavii , and  un- 
der end  of  the  Platyfma  Moyodcs  on  each  fide,  which  are  fituate'd 
anteriorly. 

The  Serati  Magni,  whreli  are  placed  laterally. 

The  Trapzii,  Latiffitm  Dor/i,  and  numerous  other  Mufcles  on 
the  Rack,  which  are  placed  pofleriorly. 

The  Intercofrales  and  Sterno-Cojlales,  which  are  fituated-  the 
former  between,  and  the  latter  on  the  inner  fide  of  the  Ribs. 

The  Bones,  confiding  of  Sternum,  Ribs,  and  Dorfal  Vertebra. 
—All  thefe  Parts,  excepting  the  Mammae,  have  been  already 
defcribed. 

MAMM2E. 

The  Mamma  are  two  Glandular  Bodies,  of  a circular  form, 
fituated  on  the  anterior,  and  a little  towards  the  lateral  parts  of 
the  Thorax,  adhering  loofely  by  Cellular  Subftance  to  the  Sur- 
face of  the  large  Pt&oral  Mufcies. 

The  term  Mamma  is  peculiar  to  the  Breads  of  Women. — In 
Men' thefe  parts  are  called  Mammilla  ; — and  in  the  Brute-kind, 
XJber# . 

In  the  Ape,  and  a few  other  animals,  they  are  placed,  as  in 
the  Human  body,  upon  the  Thorax  , — but,  in  the  generality  of 
Quadrupeds,  they  are  fituated  under  the  Abdomen. 

The  common  number  of  the  Mammae,  in  the  Human  fpecies, 
is  well  known  to  be  two. — Bartholin E,  however,  mentions  the 
cafe  of  a Woman,  who  had  two  Mammae  on  the  left  fide,  and 
one  on  the  right;  and  another,  where  there  were  two  on  each 
fide. 

Dr.  Vaughan  narrates  the  cafe  of  a Woman  he  has  examined, 
who  has  a fupernumerary  Nipple,  at  the  under  fide  of  the  right 
Mamma,  from  winch  milk  flowed  when  the  central  one  was 
preffed,  and  vice  verfa. 


6D 


'The  Mamma?  vary  in  fize  in  different  Women,  and  in  the 
fame  Women  at  different  periods  of  life. 

In  Girls,  previous  to  the  age  of  Puberty,  they  are  remarkably 
fma  )L 

About  the  age  of  fourteen,  at  which  time  the  Meries,  in 
this  climate,  moft  commonly  begin  to  appear,  they  evolve  and 
become  prominent. 

During  Geftation  they  increafe  in  fize,  and  foon  after  Delivery 
they  arrive  at  their  greateft  extent. 

After  the  age  of  forty-five,  or  from  that  to  fifty, — tire  period 
when  the  Mtsnfes  generally  difappear,  they  decreafe  in  fize,  and 
become  foft,  pendulous,  and  flaccid. 

Under  the  Skin,  there  is  a large  quantity  of  Fat  which  confti- 
tutes  a confrderable  portion  of  the  bulk  of  the  Mamma,  And  de- 
fends the  Glandular  Part,  and  is  not  found  to  pais  into,  or  com- 
municate with,  the  Ladtiferous  Dudfs. 

The  Glandular  Part  of  the  Mamma  is  of  n wliitifh  colour 
of  the  Conglomerate  kind,  and  therefore  irregular  in  its  Sub- 
ftance. 

It  is  ccmpofed  of  a number  of  fmaller  Mafles  or  Glands,  which 
are  aifo  feparated  by  Fat;  and  thefe  again  are  divided  into 
ftill  fmaller  parts,  in  which  the  Milk  is  originally  fecreted  or 
formed. 

Near  the  centre  of  the  Mamma,  is  the  Papilla  or  Nipple, 
■which  is  of  a Cylindrical  form,  and  of  a redder  colour  than  the 
reft  of  the  Skin  of  the  Breaft. 

It  is  of  different  fizes  in  different  ages  and  conftitutions,  and  is 
always  larger  in  the  time  of  Geftation,  or  of  Nurfing. 

It  is  capable  of  diftention  from  titillation,  or  when  influenced 
by  the  paffions  of  the  Mind. 

It  is  compofed  of  a tough  Cellular  or  Ligamentous  Suhjlance , 
■which  inclofes  the  Ladliferous  Tubes,  and  which  is  fo  elaftic, 
t hat  after  the  part  is  drawn  out  or  diftended,  it  readily  recovers 
its  former  dimenfion,  when  the  caufe  of  diftenfion  has  ceafed  to 
adt. 

Upon  the  Apex  of  the  Nipple,  the  Orifices  of  the  Ladfiferous 
Dudls  appear  and  are  of  the  lame  number  with  thole  which  enter 
its  Bale. 

Around  the  Nipple,  there  is  a Circle  or  Dijk,  called  Areola, 
— of  a different  colour  from  the  reft  of  the  Skin  of  the  Breaft. 

This  Difk,  however,  varies  in  colour  at  different  times  of  life, 
being  florid  in  young  Girls,  of  a pale-brown  in  Women  a lit- 
tle more  advanced  in  life,  and  in  old  age,  of  a livid,  and  dull 
colour. 

During  Pregnancy,  it  is  of  a darker  colour  than  at  other  times, 
in  confequence  of  a change  which  takes  place  in  the  Corpus  Mu. 
cofum  which  forms  it. 


1 0 

k 

Under  the  Skin  of  the  Areola,  there  are  numerous  Sebaceous 
Glands,  or  Follicles,  the  Orifices  of  which  dilcharge  an  oily  Mu- 
cin, to  defend  the  N'pple  and  Areola  around  it. 

The  Arteries  of  the  Mamma  are  partly  from  the  Internal,  and 
partly  from  the  External  Mammaries  or  Thoiacics,  the  former 
of  which  are  lent  oft'  from  the  Subclavian,  and  the  latter  from  the 
Axillary  Artery, — the  Branches  entering  the  M inima  at  many 
different  places. 

The  Veins  accompany  the  Arteries,  and  are  diftinguilhed  by 
the  fame  names. 

The  Abforbenis  of  the  Mamma  are  alfo  numerous,  the  greater 
part  of  which  pafs  through  the  Axillary  Glands,  others  penetrate 
the  Interfaces  of  the  Ribs,  near  the  Sternum,  and  enter  the 
Glands  which  belong  to  the  Internal  Mammary  Veffels. 

The  Nerajes  are  chiefly  from  the  Axillary  Plexus,  a few 
Branches  being  alfo  fenc  off  from  the  Intercoftals. 

From  the  extremities  of  the  Arteries  in  the  Subftance  of  the 
Mamma,  numberlefs  Tubes  arife,  called  DuFlus  or  Tubuli  Lac- 
tiferi,  which  gradually  unite  into  Trunks,  and  run  in  a radiated 
manner  towards  the  root  of  the  Nipple. 

They  become  grea;  ly  enlarged  in  the  time  of  Suckling,  and 
ferve  as  Refervoirs  in  which  the  Milk  is  contained. 

The  Lactiferous  DuCfs  are  accompanied,  in  the  Subftance  of 
the  Mamma,  by  a tough  white  elc.Jlic  Subjlance,  which  follows 
them  to  the  Nipple. 

At  the  root  of  the  Nipple,  they  become  contracted,  and  are 
there  from  Twelve  to  Eighteen  in  number. 

Either  from  the  want  of  uniformity,  however,  with  refpeft  to 
their  number  in  different  fubjeCts,  or  from  the  difficulty  of  per- 
ceiving them,  they  have  been  varioufly  eftimated  by  different 
Authors. 

Near  the  root  of  the  Nipple,  they  have  been  fuppofed  by  Dr. 
Meckel,  to  form  a circle  of  communication; — but  this  li3S 
been  afenbed  by  ft  11  later  Anatomilts,  to  a laceration  of  Veffels  j 
and  numerous  preparations  and  experiments, — particularly  that 
of  throwing  in  an  injeClion  at  one  Duff,  and  finding  that  it  fills 
one  part  only  of  the  Mamma,  without  returning  by  any  other 
Du6f, — teem  l’ufficiently  to  indicate,  that  there  is  no  i'uch  circu- 
lar communication. 

In  the  Subftance  of  the  Nipple,  the  La&iferous  Tubes  are  at 
a little  diftance  from  each  other,  and  are  coiled  up  in  fuch  a 
manner,  that  the  fpontaneous  flow  of  the  Milk  is  prevented,  un- 
iefs  it  be  accumulated  in  a large  quantity. 

But  when  the  Nipple  is  drawn  out  and  extended, — as  by  the 
application  of  the  Child’s  Mouth, — the  DuCts  become  ftraight 
and  parallel  to  each  other,  fo  as  to  allow  an  uninterrupted  flow 
of  the  Milk. 


71 


After  the  a£lion  of  Sucking,  the  Nipple,  and  of  conftquence 
its  Du£ts,  immediately  recover  their  former  fituation. 

Sometimes  one  or  more  of  the  La&i'ferous  Dufts  terminate 
upon  the  Surface  of  the  Areola,  from  which,  Morgagni  fup- 
pofed,  that  the  Glands  there  were  of  the  Lactiferous  kind. 

In  Children  of  both  fexes,  the  Mammae  are  merely  Cutaneous 
Tubercles,  and  at  the  time  of  birth  contain  a Milky-like  Fluid, 
which  can  be  readily  fqueez-  d out. 

This  Fluid  commonly  difappears  a fhort  time  after  Birth 
but  there  are  various  examples  on  record,  where  Milk  has  been 
brought  to  the  Breads,  both  of  young  G lismnd  old  Women,  by 
the  frequent  application  of  a Child  to  the  Nipples,  and  where 
there  was  no  caufe  for  fufpicion  of  Impregnation  be  ng  prelent. 
Nor  are  indances  awanting  of  Miik  being  brought  to  the  Mam- 
millae of  Men,  by  the  fame  application. 

The  Mamma;  add  much  to  the  ornament  of  the  perfon,  but 
lerve  in  particular  for  furn  filing  noui  ifhment  to  the  Child,  which 
is  conveyed  to  it  through  the  medium  of  the  Nipple. 

The  Secretion  begins  foon  after  Delivery,  and  continues  to 
flow  for  many  months,  and  even  for  feme  years,  if  the  Woman 
fuckle  her  Ch'ld  ; and  the  more  frequently  the  Milk  is  extra&ed, 
the  greater  is  the  quantity  received  in  a given  time. 

The  operation  of  Sucking  depends  upon  the  principles  of  the 
Air-pump.— The  child  embraces  the  Nipple  clofely  with  its  Lips, 
which  prevents  the  external  Air  from  entering,  draws  the  Dufls 
to  a draight  line,  and  prepares  a fpace  for  the  Milk,  which  is 
forced  from  the  Bread  by  the  preffure  of  the  Atmofphere,  and 
dows  to  the  Mouth  in  the  manner  a Fluid  follows  the  Piftern  of  a 
common  Pump  or  Syringe. 

INTERNAL  PARTS  OF  THE  THORAX. 

The  Mammae  and  Mufcles,  covering  the  fore  and  lateral  parts 
of  the  Thorax,  being  turned  afide,  and  the  Ribs  afterwards  cut 
from  the  Sternum  and  turned  back,  the  Internal  Parts  of  the 
Thorax  are  brought  into-view. 

They  confid  of  ihe  Pleura,  which  lines  the  Thorax  the 
MediaJUnum,  which  divides  it  into  right  and  left  Cavities,  and 
contains  feveral  Veflels,  Nerves,  &c.  between  its  Layers  the 
Pericardium  and  Heart,  which  occupy  the  middle, — and  the 
Lungs,  which  furround  the  Heart,  and  fill  the  greater  part  of  the 
Thorax. 

The  Pleura. 

The  Pleura  is  a Membrane  of  considerable  drength,  which 
lines  the  inner  fide  of  the  Thorax,  and  covers  the  mod  of  its 
contents. 

Its  External  Surface  is  Cellular,  and  adheres  clofely  to  the 
parts  which  furround  it, 

9 


72 


Its  Internal  Surface  is  fmooth  and  polijhed,  being  moiftened  by 
a Serous  Fluid,  which  exfudes  from  its  Arteries. 

It  is  divided  into  two  lateral  Sacs  or  Pleura , the  form  of  which 
covrefponds  exaftly  with  that  of  the  furrounding  Bones  of  the 
Thorax. 

The  Pleurae  adhere  to  the  Periofteum  of  the  Ribs,  line  the  In- 
tercoftal  and  Sterno  Coftal  Mufcles,  the  Sternum,  and  Dorfal 
Vertebrae,  and  cover  the  Pericardium,  Lungs,  and  Lateral  or 
Flclhy  parts  of  the  Diaphragm. 

Behind  the  Sternum,  the  Pleurae  are  contiguous  to  each  other, 
and  form  a Partition  called  Mediajlinum,  which  extends  between 
the  Sternum  and  Vertebrae,  but  is  intercepted  by  the  Heart  and 
Root  of  the  Lungs,  and  divides  the  Thorax  into  two  diftinft 
Cavities,  which  have  no  communication  with  each  other. 

The  Arteries  of  the  Pleura  are  from  thofe  of  the  adjacent  parts, 
viz.  from  the  Intercoftal,  Mammaries,  Diaphragmatics,  Bron- 
chial, and  Efophageal. 

The  Veins,  which  return  the  Blood,  accompany  the  Arteries, 
and  are  dittinguiflied  by  the  fame  names. 

The  Nerves  are  from  the  Intercoftals  and  Diaphragmatics,  but 
too  fmall  to  be  traced  without  difficulty  ; and  the  Membrane  it- 
felf  is  not  obferved  to  poflefs  much  fenlibility  in  the  found  un- 
inflamed ftate. 

The  Pleura  ferves  to  render  the  in  fide  of  the  Thorax  fmooth, 
for  the  eafy  motion  of  the  contiguous  parts,  to  divide  it  into  Ca- 
vities, and  to  (Lengthen  the  containing  and  contained  parts  of 
the  Thorax. 

Mediastinum. 

The  Mediajlinum , fo  named  from  its  fituation  in  the  middle  of 
the  Thorax,  is  formed  by  a reflexion  of  the  Pleura,  and  is  of 
courfe  double. — It  contains  between  its  Layers  a confiderable 
quantity  of  Cellular  Subftance,  by  which  they  are  united. 

It  is  divided  into  Anterior  and  Pojlerior  Mediaftinum,  the  for- 
mer of  which  is  fituated  at  the  fore,  and  the  latter  at  the  back- 
part  tff  the  Thorax. 

The  Anterior  MedvaJUnutn  is  conne&ed  before,  to  the  Ster- 
num ; and  behind,  to  the  Pericardium  and  large  Veflels  of  the 
Heart. 

The  two  Layers  of  the  Anterior  Mediaftinum  ar«  clofely  ap- 
plied to  each  other,  excepting  at  the  upper-part  of  the  Thorax, 
where  they  are  feparated  by  the  remains  of  the  'Ihymus  Gland. 

At  the  upper-part  of  the  Thorax,  it  lies  exaftly  behind  the 
middle  of  the  Sternum  ; but  in  its  defcent,  it  inclines  gradually 
to  the  left  edge  of  that  Bone. 

In  confequence  of  its  obliquity,  a pointed  inftrumerrt,  puffier? 
through  the  centre  of  the  Sternum,  is  generally  found  to  pafs 
into  the  right  Cavity  of  the  Thorax. 


T6 


Frequent  deviations,  however,  from  this  general  rule,  have  been 
met  with. — In  particular,  Lieutaud  and  Sabatier,  relate  fe- 
veral  inftances  where  the  Anterior  Mediaftinum  was  found  to 
delcend  along  the  middle  of  the  Sternum;  and  others,  though 
rare,  where  it  defcended  even  to  the  right  hde  of  this  Bone. 

The  Pofterior  Mediaftinum  reaches  from  the  root  of  the  Lungs 
and  back-part  of  the  Heart,  to  the  Dorfal  Vertebrae. 

Between  the  Layers  of  the  Pofterior  Mediaftinum,  a triangu- 
lar ftpace  is  formed,  in  which  are  fituated  the  under  end  of  the 
Trachea,  the  Efophagus,  the  Ao.ta  Defcendens,  the  Vena  Azy- 
gos,  and  Thoracic  Du£t,  wth  the  Eighth  Pair  of  Nerves. 

The  Blood-vejj'sls  of  the  Medaftinum  are  from  thofe  of  the 
neighbouring  parts  : — The  Anterior  Mediaftinum  is  l'upplied  by 
Branches  from  the  Subclavian,  Internal  Mammaries,  and  Dia- 
phragmatic;.,— and  the  Pofterior  Mediaftinum,  by  Branches  from 
the  Intercoftals  and  Elbphageals. 

The  Feins  accompany  the  Arteries,  and  have  the  fame  names. 

The  Mediaftinum  divides  the  Thorax  into  two  Cavities,  fup- 
poi  ts  its  general  Contents,  hinders  one  Lung  from  prefilng  upon 
the  other,  when  the  peifon  lies  on  his  fide,  and  prevents  Fluids, 
— whLh,  in  coniequence  of  acc  der.t  or  difeafe,  may  be  contain- 
ed in  the  Cavitj  of  the  Thorax, — from  palling  from  one  fide  to 
the  other. 

Pericardium. 

The  Pericardium,  Sac,  or  Capfule  of  the  Heart,  is  one  of  the 
itrongeft  Membranes  of  the  Body,  and  its  fize  fuch  as  to  be  pro- 
perly adapted  to  that  of  the  Heart,  which  it  contains. 

It  is  formed  of  tnuo  Layers,  the  External  of  which  is  a conti- 
nuation of  the  Anterior  Mediaftinum,  which  afterwards  paffes  to 
the  Lungs  and  lateral  parts  of  the  Diaphragm. 

The  Internal  Layer  is  l'mooth,  tendinous-like,  and  polilhed  on 
its  inner  Surface,  and  is  ftronger  than  the  other. 

It  adheres  fo  firmly  to  the  Tendinous  part  of  the  Diaphragm, 
as  not  to  be  l'eparatcd  from  it  without  much  difficulty. 

The  Pericardium  extends  a confiderable  way  beyond  the  Bafe 
of  the  Heart,  and  includes  the  large  Blood- velfels,"  as  far  as  the 
roots  of  their  firft  principal  Branches,  in  coniequence  of  which 
it  forms  leveral  angles,  which  have  been  termed  Cornua  of  the 
Pericardium. 

While  the  External  Layer  is  reflected  to  cover  the  parts  which 
furround  it,  ihe  inner  one  is  aifo  reffefted,  firft  over  the  roots  of 
the  large  Blood- veffels,  and  then  over  the  Heart,  to  form  its 
proper  covering,  in  the  fame  manner  the  Tunica  ConjumStiva  is 
reflected  from  the  Eye- lids  to  cover  the  fore-part  of  the  Eye. 

From  the  ends  of  the  Extreme  Arteries,  upon  its  Surface,  a 
Fluid,  called  Liquor  Pericardii,  is  difcharged,  by  which  it  is  lu- 
bricated, and  the  efte&s  of  Fri&ion  diminilhed. 

Vox.  II.  G 


The  Liquor  Pericardii  is  commonly  found,  after  death,  in  the 
quantity  of  a few  drachms,  though  not  unfrequently  of  one  or 
.two  ounces. 

Its  colour  is  redder  in  a young  iubje£I,  than  in  a perfon  ad- 
vanced in  life,  in  whom  it  becomes  paler,  or  more  of  a ftraw- 
colour. 

The  Arteries  of  the  fore-part  of  the  Pericardium  are  from  the 
Internal  Mammaries  and  Biaphragmaties ; thofe  of  its  fore-part 
from  the  Bronchial  and  El'ophageal. 

The  Veins  correfpond  with  the  Arteries,  and  have  the  fame 
name. 

The  Ufe  of  the  Pericardium  is,  to  preferve  the  Heart  in  fitu, 
.to  defend  it  from  being  injured  by  the  parts  which  furround  it, 
and  to  rtftrain  its  inordinate  motions. 


OF  THE  HEART. 


TitE  fleart  is  a hollow  Mufcle,  divided  into  different  Cavi- 
ties, and 'inclofed  in  the  Pericardium. 

It  is  fituated  in  the  Cavity  of  the  Thorax,  behind  the  Sternum, 
fcetween  the  Right  and  Left  Lungs. 

It  is  of  a Conical  figure,  flattened  at  one  fide,  and  is  divided 
into  Bafe,  Body,  and  Apex.,  with  a Superior  and  Inferior  Surface, 
and  a Right  and  l.ejt  Margin. 

The  Bafe  is  placed  backwards  next  the  Spine,  while  the  Body 
and  Apex  are  turned  forwards,  anil  obliquely  over  to  the  left 
fide. 

In  Quadrupeds,  the  Heart  is  placed  upon  a line  with  the  Ster- 
num, the  point  only  touching  the  Diaphragm  : — In  the  Human 
Body,  the  Apex,  or  Point  of  the  Heart,  is  but  little  lower  than 
the  Bafe,  and  projects  between  the  two  lobes  of  the  left  Lung, 
Beh'nd  the  Cartilages  of  the  Fifth  and  Sixth  True  Ribs  of  the 
left  Side,  or  a little  below  the  left  Nipple,  where  the  Pulfation 
may  be  felt. — The  fituation,  however,  vai  ies  a little,  according 
to  the  pofition  of  the  Body,  and  ftate  of  Refpiration. 

Though  this  be  the  common  fituation  of  the  Heart,  a few  rar* 
3nd  fingular  inffances  have  occurred,  where  it  has  been  found  to 
occupy  the  right  fide  of  the  Thorax;  and  a difplacement  has 
fometimes  happened,  in  confcquence  of  different  kirds  of  tu- 
mours m tire  left  fide  of  the  Thorax. 

The  Superior  or  Anterior  Surface  of  the  Heart  is  convex,  and 
is  oppofed  to  the  Pofterior  Surface  of  the  Sternum,  the  anterior 
edges  of  the  Lungs  intervening. 

The  Inferior  or  Poferior  Surface  is  flat,  and  refrs  upon,  the 
Tendon  of  the  Diaphragm,  which  fupports  it;  the  Heart  is  not 


much  affefted,  however,  by  the  motions  of  that  Mufcle  in  time 
of  Refpiiation,  its  Tendon  moving  only  in  a fmall  degree. 

The  right  tide  of  the  Body  of  the  Heart  is  fharp,  and  is  cal- 
led Margo  Acuius. 

The  left  tide  of  the  Body  of  the  Heart  is  round,  and  is  termed' 
Margo  ObtufuS. 

rire  Bale  is  formed  of  a right  and  left  Auricle , and  the  Body 
of  a right  and  left  Ventricle. 

When  the  Heart  is  defended,  the  right  Auricle,  and  part  of  the 
cori efponding  Ventricle,  occupy  the  right,  and  the  relt  of  the 
Heart  the  left  Cavity  of  the  Thorax. 

The  Heart  is  connefted  above  and  behind  to  the  upper  and 
back-part  of  the  Thorax,  through  the  medium  of  the  great  Vef- 
fels  wh  ch  go  into,  or  pal's  out  from  it. 

The- other  parts  of  the  Heart  are  free,  be. ng  merely  contigu- 
ous to  .he  inlhle-of  the  Pericardium. 

TheEx.emal  Surface  ef  the  Heart  is  covered  with  a thin 
frnooth  Membranous  Coat , which  is  a retleftion  of  the  inner  Layer 
of  the  Pericardium,  and  which  gives  additional  ftrength  to  its 
Flclhy  Fib  es. 

Between  the  Coat  and  Subftance  of  the  Heart,  there  is  com- 
monly a confiderable  quantity  or  Fat,  which  lubricates  it,  and 
■facil  tales  its  motions. 

The  Subdance  of  the  Heai  t con  lifts  of  Mufcular  Fibres,  firm 
and  more  ciolely  connected  than  the  generality  of  Fibres  of  Mul- 
cles  in  otlver  parts  of  the  Body. 

The  Fibres  run  in  different  directions,  longitudinal  and  tratif- 
verfe,  but  molt  of  them  oblique. 

Many  of  them  run  over  the  Po>nt  of  the  Heart  from  one  Sur- 
face to  the  other,  and  the  whole  lo  much  twilled  and  folded,  and 
ib  varioufly  intermixed,  as  to  be  difficult  to  be  unravelled  or  de- 
feribed  : — In  general,  however,  their  couife  is  l’ucli  as  to  leffen 
the  Cavities  of  the  Heart  in  all  their  dimensions. 

The  Cavities  of  the  Heart  are  lined  wth  a Membrane  extreme- 
ly thin,  but  denfe  and  ftrong,  to  defend  them  againtt  the  pref- 
fure  of  the  Blood. 

The  Heart  is  formed  of  an  anterior  or  right  and  a poferior  or 
left  hde,  or  of  a right  and  lejt  Hea  t . j fined  together  by  a Par- 
tition, which  prevents  the  two  fides  from  having  any  d left  com- 
munication with  each  other. — The  lenns  Right  and  Letr,  how- 
ever, are  more  applicable  to  the  Heai  t of  the  Quadruped,  and 
thofe  of  Anterior  and  Pofterior  to  the  Human  Heart. 

Each  ; de  of  the  Heart  is  fui  milled  w.th  a let  of  Veins,  with 
an  Auricle,  a Ventricle,  and  an  Artery,  and  alio  with  two  lets  of 
Valves, — one  between  the  Auricle  and  Ventricle,  the  other  be- 
tween the  Ventricle  and  Artery. 

At  the  right  fide  of  the  Heart  are  two  Veins,  ca’letl  horn  their 
large  fize  Vena  Cavaf  the  one  Superior , the  other  Inferior. 


76 


The  Superior  Vena  Cava,  called  alfo  Vena  Cava  Defcendens , 
returns  the  Blood  from  the  upper  parts  of  the  Body;  and  the 
Inferior  Vena  Cava,  termed  likewise  Afcendens , returns  it  from 
the  lower  parts  ; and  both  terminate  in  the  right  Auricle.  It  is 
prevented  from  returning  by  the  fullnefs  of  the  Veins,  and  by 
the  preffure  of  the  Blood  a tergo. 

The  Auricle  is  fituated  upon  the  right,  and  partly  upon  the 
back-part  of  the  Heart,  and  is  divided  into  the  right  Sinus  Veno- 
fus  and  proper  Auricle. 

The  Sinus  Venofus  is  formed  by  the  union  of  the  two  Vena? 
Cavae,  which  i'weil  out  towards  the  anterior  and  left  fide.  It  is 
notched  at  its  anterior  edge,  is  a Mufcular  Bag  of  confideiflbie 
ftrength,  and  is  unifot  m and  fmooth,  both  upon  it*  outer  and 
inner  Surface. 

At  the  upper  and  left  fide  of  the  Sinus,  is  the  projection  or 
Appendix,  teimed  Proper  Auricle,  from  its  fuppofed  refemblance 
to  the  Ear  of  a Quadruped  : — It  is  formed  by  a blind  Sac,  which 
is  ferrated  and  notched  on  its  poflerior  edge,  and  convex  or 
rounded  on  the  other,  and  terminates  obliquely  in  an  obtufe 
point. 

' The  Sinus  and  proper  Auricle  form  one  common  Cavity,  have 
no  Valve  between  them,  and  are  therefore  filled  and  emptied  at 
the  fame  time. 

Where  the  t.vo  Cavities  meet  in  the  Hearts  of  Quadiupeds, 
there  is  a Projection  feen  in  the  Sinus  Venofus,  called  Tuberculum 
LOWER!,  which  is  fuppofed  to  prevent  the  Blood  of  the  one  Ca- 
va from  rufhing  upon  that  of  the  other,  and  to  diredt  it  into  the 
Auricle. 

At  the  meeting  of  the  two  Cavae  in  the  Human  Heart,  an  an- 
gle is  formed,  which  alfo  has  fiequently  got  the  name  of  Tuber- 
culin?] Loweri  : — That  fubftance,  however,  is  peculiar  to  the 
Hearts  of  Brute-Animals. 

Under  tins  Angle,  or  joining  of  tlie  Venae  Cava?,  there  is  the 
Veftige  of  the  foramen  Ovale,  which,  in  the  Foetus,  forms  a 
communication  between  the  right  and  left  Auricles  ; but,  in  the 
Adult,  is  filled  up  by  its  Membrane,  and  foims  the  Ft  fa  Ova- 
lis. 

The  Foffa  Ovalis  has  thick  and  ffiong  fides,  called  Column* 
Foraminis  Ova/is,  Iftbmus  Vieussenii,  or  Annulus  Fofj'a  Ova- 
lis. 

At  the  left  fide  of  the  Mouth  of  the  Inferior  Cava,  where  it 
joins  the  Sinus,  is  the  Valve  of  Eustachius. 

It  is  in  form  of  a Crefcent,  with  the  convex  edge  fixed  to  the 
union  > f the  Sinus  and  Cava,  and  the  concave  edge  turned  ob- 
liquely upwards,  reaching  about  half  way  over  the  Mouth  of 
the  Cava. — Its  fize  and  appearance,  however,  vary  much  in  dif- 
fident Subje&s. 


77 

Its  pofterior  Cornu  is  continued  with  the  left  fide  of  the  Ifth- 
mus  of  the  Foramen  Ovale ; the  other  end  vanilhes  in  the  oppo- 
fite  fide  of  the  Sinus. 

It  is  equally  ditfinft  in  the  Adult  as  in  the  Foetus  ; but  in  the 
former  it  is  frequently  found  reticulated,  or  Cribiiform,  which 
appearance  is  l'eldom,  though  fometimes,  met  with  in  the  latter. 

In  the  Adult,  it  is  fuppofed  to  prevent  the  Blood  of  the  Au- 
ricle from  palling  into  the  Inferior  Cava;  and  in  the  Foetus,  to 
direft  the  Blood  of  the  Inferior  Cava  to  the  Foramen  Ovale. 

Upon  the  left  tide  of  the  Valve  of  Eustachius,  in  the  under 
part  of  the  Auricle,  s the  Orifice  or  Termination  of  the  g. eat 
Coronary  Vein  of  the  Heart. 

Over  the  Orifice  of  this  Vein,  there  is  a Semilunar  Valve,  to 
prevent  the  Blood  in  the  Auricle  from  palling  into  the  Vein. 

The  inner  fide  of  the  proper  Auricle  is  readily  dillinguilhed 
from  the  Sinus,  by  having  a number  of  Columns  Carnes,  or 
Flejhy  Pillars  in  it,  which,  from  their  fuppoied  rei’emblanee  to 
the  Teeth  of  a Comb,  fometimes  obtain  the  name  of  Mufculi 
Auricula  Pechnati. 

The  Mufculi  Pe&inati  have  fmalier  Columns  running  in  dif- 
ferent diiv£Vons,  giving  the  whole  a reticulated  appearance. 

Between  the  Column*  Carneae,  are  Deprejjions  or  Furronus,  in 
which  the  tides  of  the  Auricle  are  thin,  and  femi • tranfparent, 
being  chiefly  formed  by  the  outer  and  inner  Membrane  of  the 
Auricle. 

At  the  under  and  left  fide  of  the  Sinus  Venofus,  and  oppofite 
to  a Groove,  fitilated  externally  between  the  Auricle  and  Ventri- 
cle, there  is  a Hols,  above  an  inch  in  diameter,  which  opens  in- 
to the  upper  and  right  part  of  the  correfponding  Ventricle. 

The  right  Auricle  receives  the  Blood  from  the  Vense  Cavas 
and  Coronary  Veins,  and,  by  its  MufcuUr  contra&ion,  difchar- 
ges  it  into  the  correfpondmg  Ventricle,  out  of  which  it  is  pre- 
vented from  returning  oy  a Valve,  called  Tricufpid , placed  with- 
in the  Ventricle. 

The  Right  or  Pulmonary  Ventricle,  is  fit ua ted  on  the  fore-fide 
of  the  Heart,  is  of  a triangular  form,  and  much  thicker  and 
Wronger  than  the  correfponding  Auricle. 

it  iias  many  itrong  Eminences,  Columns,  Lacertuii,  or  Cords, 
called  Colamna  Carnes. 

The  Columns  run  in  different  directions,  but  the  ftrongeft  of 
them  longitudinally,  and  tie  or  various  iizcs,  forming  fo  many 
diitinft  Muicles,  which  are  extremely  compaft  in  their  ftruc- 
ttire,  and  compofe  a beautiful,  intricate,  and  irregular  Net- 
woik.  ' 

In  general,  they  adhere  through  their  whole  length  to  each  o- 
ther,  or  to  the  fidcs  of  the  Ventricle;  but  many  of  them  are  loofe 
;n  their  middle,  and.may  be  railed  by  a probe  put  under  them. 

Yoi„  II.  G 3 


78 


They  affift  the  Ventricle  in  its  SjJlole  or  contraction,  and  pre- 
vent it  from  bei n oveiftretched  in  it:  Dyajt'le  or  dilatation,  and 
agitate  the  Blood  in  its  palfage  through  the  Ventricle. 

They  are  fuppofed  to  bring  the  oppofite  Tides  of  the  Ventricle 
completely  together,  during  its  contraction. 

Between  the  Columnae  are  many  deep  Grooves,  Pits,  01F0- 
veae,  into  all  of  which  the  Blood  readily  enters. 

Around  the  Paffige,  between  the  Auricle  and  Ventricle,  there 
is  a tendinous  Margin  or  Ring,  from  the  whole  edge  of  which 
a circular  Membrane  is  fent  off,  called  Valvula  Tricufpis,  or  Tn- 
glochin,  from  its  having  thiee  principal  points  or  divisions. 

From  the  edge  of  the  Tricufpid  Valve,  many  1’mall  round 
'Tendinous  Cords  are  fent  off,  of  unequal  fize. 

The  Chorda  Tendinea  defcend  obliquely  within  the  Ventricle, 
in  the  fame  direction  with  the  Valve  from  which  they  arife. 

They  are  fixed  to  the  extremities  of  a few  ftrong  Papillae  or 
Columnae  Caineae,  which  are  joined  by  their  other  extremites  to 
the  comlpondmg  fides  of  the  Ventricle. 

The  Tricufpid  Valve  prevents  the  reflux  of  the  Blood  to  the 
Auricle,  during  the  contraction  of  the  Ventricle. 

The  Tendons  allow  the  Valve  io  be  puffied  back  by  the  Blood, 
until  a Septum  or  Partition  is  formed  by  it  at  the  Mouth  of  the 
Ventricle,  during  the  contraction  of  the  latter.— The  Papillae,  by 
their  contraction,  prevent  the  Valve  from  going  into  the  Auri- 
cle. 

The  Valve  is  opened  and  prefi'ed  back  by  the  Blood  in  its  paf- 
fage  from  the  Auricle  to  the  Ventricle. 

The  upper  and  left  fide  of  the  Ventricle  becomes  fmooth  and 
uniform,  and  leads  to  a large  Opening,  about  an  inch  in  diame- 
ter, which  is  the  Mouth  of  the  Pulmonary  Artery. 

The  right  Ventricle,  by  its  dilatation,  receives  the  Blood  from 
the  Auricle,  and  fends  it,  by  a thong  and  hidden  convuifive 
contraction,  to  the  Pulmonary  Artery,  from  whence  it  is  pre- 
vented from  returning,  by  three  Valves  placed  in  the  Mouth  of 
the  Artery. 

The  Valves  at  the  Mouth  of  the  Pulmonary  Artery  are  called 
Valvula  Semilunares,  or  Sigmoidea,  from  the  refemblance  of 
their  edges  to  thofe  of  a Crefcent. — Two  of  them  are  placed  in 
the  fore,  and  one  in  the  back-part  of  the  Artery. 

Each  cf  them  forms  a fmall  Sac,  one  edge  of  which  adheres 
to  a third  part  of  the  circumference  of  the  infide  of  the  Artery  ; 
the  other  edge  is  loofe  in  the  Cavity  ot  that  Veffel,  and  is  fotne- 
what  thicker  and  ftronger  than  th#  teff  of  the  Valve,— the  thick- 
ened edges  ferving  as  Ligaments  to  it. 

The  loofe  edge  has  a general  Curve,  divided  into  tvso  fmaller 
ones,  which  meet  in  a point  in  the  middle. 

The  Valves  are  chiefly  formed  of  a doubling  or  exttnfion  of 
the  inner  Coat  of  the  Artery. 


In  the  middle  point  or  loofe  edge  of  each  of  the  Valves,  there 
is  a fmall  hard  triangular  Granula,  of  a fomewhat  redder  colour 
than  the  relf  of  the  Valve,  called,  from  its  reputed  dilcoveries, 
Corpufculum  Au R ant ii,  or  Corpufculum  Morgagni  ; or  from 
its  rel'emblance  in  fhape  to  the  Sefamum  feed,  Corpufculum  Sefa- 
moideum. 

The  Corpufcles  complete  the  Valves  at  the  centre  of  the  Arte- 
ry, and  enable  them  to  make,  a ftronger  reiiftance  againfl  the 
B.ood,  while  the  Artery  is  in  a£bon. 

The  Semdunar  Valves  zee. con  cave  towards. the  Artery,  convex 
towards  the  Ventricle,  and,  when  fliut,  their  loofe  edges  are  op- 
pofed  to  each  other,  fo  as  to  enable  them  to  form  a complete  Par- 
tition between  the  Ventricle  and  Artery. 

Oppofite  to  the  Semilunar  Valves,  the  Artery  bulges  out,  and 
forms  three  Projections,  which  have  correfponding  Pitts  or  De- 
preflions  within,  and  are  called,  from  their  defcoverer,  Sinus 
Valsalva. 

The  Sinufes  of  Valsalva  are  of  the  fame  nature  w:th  thofe  Di- 
latations which  are  found  in  the  Veins  and  Lymphatics,  between 
their  Tides  and  Valves  ; and,  like  them,  are  partly  formed  by  the 
prefiure  of  the  Fluids  upon  the  tides  of  the  Velfels. 

The  Pulmonary  Artery  receives  the  Blood  from  the  right 
Ventricle,  and  by  its  contractile  power,  aflilts  the  Ventricle  in 
driving  it  through  the  Lungs. 

The  Semilunar  Valves,  preffed  back  by  the  Blood  in  the  Ar- 
tery, prevent  its  return  into  the  Ventricle. 

The  Valves  are  opened  again  by  being  driven  towards  thefides 
of  the  Artery  by  the  current  of  the  Blood,  upon  the  next  con- 
traction or  ftroke  of  the  Ventricle. 

The  Pulmonary  Artery  pafl'es  behind  the  Sternum,  and  fepa- 
rates  into  right  and  left  Branches,  which  go  to  the  correfponding 
parts  of  the  Lungs. 

The  two  Branches  of  the  Pulmonary  Artery,  like  thofe  of  the 
Arteries  of  he  Vifcera  in  other  pans  of  the  large  Cavities,  fud- 
denly  divide  into  Itill  fmaller  Branches. 

From  the  extreme  Arteries  of  the  Lungs,  correfponding  Veins 
arife,  and  are  merely  the  continuation  or  reflection  of  the  Arte- 
ries, without  any  intermediate  Cell " or  Dilatations. 

The  Pulmonary  Veins,  in  the  Su-'ftance  of  the  Lungs,  srradu- 
ally  unite,  and  form  four  principal  Trunks , which  terminate  in, 
and  carry  the  Blood  to  the  left  Auricle. 

Of  the  Pulmonary  Veins,  two  come  from  the  right,  and  two 
from  the  left  lung,  and  terminate  m the  correfponding  Tides  of  the 
left  Auricle. 

The  left  Auricle  is  confiderably  thicker  and  A:  onger  than  the 
right,  and,  like  it,  is  divided  into  Sinus  Veubfus.  and  proper 
Auricle,  which  from  one  common  Cavity  without  the  interven- 
tion of  any  Valve. 


80 


The  left  Sinus  Venofus,  called  alfo  Sirius  PulmQnalis,  is  turned 
towards  the  Spine,  is  more  of  a cubic  form  than  the  right  one  j 
but  refenrbles  it  in  the  uniformity  and  fmoothnefs  of  its  outer 
and  inner  Surfaces. 

From  the  fore  and  left  part  of  the  Sinus,  the  Proper  Auricle 
projects,  and  forms  a diftintf  flat  Appendix,  or  Bag,  with  dif. 
ferent  Curvatures  or  Indentations  upon  its  edges. 

The  inner  part  of  the  Proper  Auricle  is  longer,  but  narrower 
than  that  on  the  right  fide  , like  it,  however,  it  is  formed  of 
Columns  Carnete,  with  Furrows  between  them. 

The  Proper  Auricle  is  fomewhat  lefs  capacious  than  that  on 
the  right  fide  j but  the  Smus  is  as  much  larger  as  to  tender  the 
two  common  Cavities  of  the  right  and  left  Auricles  nearly 
equal. 

The  two  Auricles  have  a Plefby  Septum  between  them,  in  which, 
as  has  been  already  mentioned,  there  is  the  Foramen  O-vale  in  the 
Foetus  ; — but  in  the  adult  the  Partition  is  generally  perfefl. 

From  the  under  part  of  the  Sinus  Venofus,  a PaJJage  leads 
down  to  the  Cavity  of  the  Left  Ventricle,  and  is  oppolite  to  a 
Grove  Celt  externally  between  the  Auricle  and  Ventricle,  fimilar 
to  that  on  the  right  fide. 

The  Left  Auricle  receives  the  Blood  from  the  Pulmonary 
Veins,  and  by  its  Mufcular  contraction,  drives  it  into  the  Left 
Ventricle,  from  which  it  is  prevented  from  returning,  by  a Valve 
in  the  Ventricle,  called  Mitralis. 

The  Left  Ventricle  is  lituated  in  the  pofterior  and  left  part  of 
the  Heart. 

Its  fides  are  about  three  times  thicker  and  fronger  than  thofe  of 
the  Right  Ventricle,  being  in  proportion  to  the  force  required  to 
propel  the  Blood  to  the  moil  remote  parts  of  the  Body. 

It  is  nanower  and  rounder,  but  coniider  bly  longer,  both  on 
its  External  Surface  and  in  its  Internal  Cavity,  than  the  R:ght 
Ventricle,  and  generally  defcends  fumeway  below  the  other,  and 
forms  the  Apex  cordis,  or  Point  of  the  Heart. 

The  Cavity  is  commonly  defcribed  as  being  lefs  than  that  of 
the  Right  Ventricle  ; — But  the*  apparent  difference,  which  takes 
place  after  death,  is  accounted  tor  with  feemii  g propriety  by  fome 
Authors, — from  the  left  Ventricle  being  tic  ■ c r the  me  ft  part 
found  empty,  and  the  Right  one  full,  and  front  cite,  g:  inter  de- 
gree of  contraftiiity  n die  former 

That  the  capacity  of  the  Cavity  cf  t!  e ripht  ami  1-  , t dec  of 
the  Heart  is  more  nearly  equal  during  lire  that  after  cl  ath,  or 
than  it  is  generally  fuppofed  to  be  . tv  -mv-  re.  tne  ar.  earance 

of  the  Heart  of  the  Human  ai.d  ;»o  of  > i ; k nn,  ami  .torn 

inj  flions  nto  the  two  Tides  of  the  f.-'iic  where  the  : tree  ap- 
plied is  in  pro"  ition  to  the  relative  It  re ; cth  r i 1 < 

The  inner  Sm  face  of  the  Left  Ventricli  has  h > fame  general 
appeal ance  with  the  Ventricle  of  the  ng.  i flue,  and  only  d.fters 


SI 


from  it  in  having  ns  Column*  Came*  larger,  firmer  and  ftvong- 
er. 

In  the  Paffage  of  communication  between  the  Auricle  and 
Ventricle,  there  is  a Ring,  from  which  a Circular  Palms  goes 
off,  with  all  its  apparatus  fimilar  to  that  between  the  right  Au- 
ricle and  Ventricle,  and  differing  in  no  reipeft  from  it  in  llru&ure 
and  ufe,  excepting  in  being  ftronger,  and  in  being  divided  into 
two  principal  portions  only. 

This  Valve  has  been  fuppofed  to  bear  fome  refemblance  to  a 
Bijhop's  Mitre,  from  which  it  has  been  called  Palmula  Mitralis. 

One  of  the  portions  of  this  Valve  is  larger  than  the  other,  lies 
over  the  Mouth  of  the  Aorta,  and  is  fuppofed  to  cover  it  while 
the  Ventricle  is  a filling. 

The  Palmula  Mitralis  prevents  the  reflux  of  the  Blood  during 
the  cor.traftion  of  the  Ventricle. 

After  the  coatraction  is  over,  the  Valve  returns  to  its  former 
fituation  by  the  impulle  of  a frelh  current  of  Blood  from  the  Au- 
ricle. 

Between  the  Right  and  Left  Ventricle,  there  is  a thick  ftrong 
impervious  Partition,  wlrch  forms  a fhare  of  the  general  Septum 
Cordis,  and  is  compofed  partly  by  the  wall  of  the  Right,  but 
chiefly  by  that  of  the  Left  Ventricle,  the  Right  being  united  to 
the  Left,  almoft  in  the  form  of  an  Appendix. 

The  Partition  prevents  any  dirett  communication  between  the 
two  Ventricles. 

• Oppofite  to  the  outer  edge  of  the  Septum,  both  upon  the  up- 
per and  under  Surfaces  of  the  Heart,  there  is  a Groome  in  which 
fome  of  the  principal  Trunks  cf  the  Coronary  Veflels  are  fitu- 
ated. 

At  the  fore  and  right  fide  of  the  Valvula  Mitralis,  and  behind 
the  beginning  of  the  Pulmonary  Artery,  there  is  a round  Opening 
which  is  the  Mouth  of  .he  Aorta,  and  which  is  nearly  of  the 
lame  fize  wiih  that  of  the  Pulmonary  Artery. 

Under  this  opening,  the  Surface  of  the  Ventricle  becomes 
fmootb,  and  equal,  having  none  of  the  Columnse  Came*  which 
are  l'een  on  the  other  parts  of  its  Cavity. 

The  Left  Ventricle  receives  the  Blood  fent  to  it  from  the  Au- 
ricle, and  by  a contraffion  fimiar  to,  but  much  ftronger  than 
that  of  the  Right  Ventricle,  propels  it  to  the  Aorta. 

At  the  Mouth  of  the  Aorta,  there  are  three  Semilunar  Palmes, 
with  the'r  Corpufcula  Aur  an  Tir,  perfectly  fimilar  to  thole  of  the 
Pulmonary  Artery; — but  a little  ftronger. 

On  the  outiideof  the  Semilunar  Valves,  are  the  Sinufss  of  Val  - 
salva,  like  thofe  of  the  Pulmonary  Artery, — but  a little  more 
prominent. 

The  Semilunar  Valves  are  prefled  back  by  the  Blood,  and  pre- 
vent its  reflux  during  the  contraftion  of  the  Aorta.-— They  are 


82 


returned  towards  the  Tides  of  the  Aorta,  in  the  fame  manner, 
and  from  the  lame  caufe,  as  in  the  Pmmonaiy  Artery. 

The  Aorta  paffes  upwards  from  ihe  top  of  the  Left  Ventricle, 
and  is  lituated  fit  It  behind,  and  then  on  the  right  line’'  of  the 
Pulmonary  Artery,  and  betwen  it  and  the  Superior  Cava. 

It  bears  nearly  the  lame  proportion  in  thicknefs  and  Itrength 
to  the  Pulmonary  Artery,  which  the  Tides  of  the  Left  Ventricle 
do  to  thole  of  the  Right. 

When  the  Aorta  is  about  to  fend  off  the  full  of  its  large 
Branches  at  the  top  of  the  Thorax,  it  is  f great  fize,  and  is 
fometimes  called  the  Large  Sinus  of  Valsalva. 

The  Aorta  receives  me  Blood  from  the  Left  Ventricle,  and  by 
its  Muicular  contraftiun  re-afts  upon  it,  and  aflilhi  the  Ven- 
tricle in  fending  it  by  numberlels  Branches  through  the  d ft’erent 
parts  of  the  Body,  from  whence  it  is  returned  by  the  Veins  to 
the  Rit  lit  Auricle. 

B.eiides  the  Blood -veflels  already  taken  notice  of,  and  which 
are  common  to  the  Heart  and  the  red  of  the  Body,  the  Heart  is 
furn. filed  with  Veffels  peculiar  to  itlelf,  termed  Coronary  from  a 
Corona  which  they  form  upon  its  fuiiace. 

The  Coronary  Velfels  con  lift  of  two  Arteries  and  one  principal 
Fein, 

The  Coronary  Arteries  arife  from  the  Sin  life- , at  the  Mouth  of 
the  Aorta,  oppufite  to  two  of  the  Semilunar  Valves. 

One  tuns  in  a Groove  between  the  Right  Auricle  and  Ventri- 
cle, and  fupplies  chiefly  the  right  fide  of  the  Heart. 

The  other  paffes  partly  between  the  Left  Auricle  and  Ventri- 
cle, and  partly  in  the  Groove  between  the  Ventricles,  on  the  fore- 
fide  of  the  Heart,— fupplying  the  left  fide  of  the  Heart,  and  com- 
municating wuh  the  Branches  of  the  other  Artery  on  its  upper 
and  under  Surfaces. 

The  Coronary  Arteries  are  entirely  difperftd  upon  the  fubflance 
of  the  Heart,  and  upon  the  roots  of  the  great  Veffeb,  forming 
upon  thef’e  fume  of  the  minute  Blanches,  termed  Fafa  Faforum. 

The  Coronary  Arteries,  from  their  fituation  oppofite  to  the 
Valves,  have  been  fuppofed  to  be  filled  at  a different  time  from- 
that  of  ihe  reft  of  the  Aiterious  Syftem  ; — but  from  experiment, 
it  Teems  now  AifRcient ly  evident,  that  the  Coronary  Veffels  have 
their  puliation  at  the  fame  inltant  with  the  other  Arteries. 

The  Coronary  Feins  return  the  Blood  from  their  correfponding 
Arteries  : The  greater  part  of  them  join  into  a Trunk.,  called 
the  Great  Coronary  Fein,  which,  after  making  a turn  from  the 
left  fide,  and  running  between  the  Left  Auricle  and  Ventrcle, 
terminates  in  the  under  part  of  the  Right  Auricle,  where  it  i9 
covered  by  its  Semilunar  Valve. 

Other  Coronary  Veins,  much  fmaller  than  the  former,  termi- 
nate in  different  parts  of  the  right  fide  of  the  Heart. 


The  Abforbents  o f the  Heart  go  to  the  neighbouring  Lympha- 
tic Glands. 

The  Nerves  are  from  the  great  Sympathetics  and  Eighth  Pair. 

With  refpedl  to  the  Circulation  in  general  : — The  Veins  re- 
turn the  Blood  from  all  the  different  parts  of  the  Body  by  a flow 
and  equal  motion,  and  without  puliation,  to  the  Aui icles,  which 
on  account  of  the  quantity  and  ffimulating  quality  of  the  Bicod, 
contrail  fuddenly  and  at  the  lame  time,  and  fend  it  to  the  Ven- 
tricles. 

The  Ventricles,  from  the  fame  caufe  which  (Emulates  the  Au- 
ricles, and  from  the  ffroke  they  receive  from  them,  contraftcon- 
vulfively,  with  a force  proportioned  to  the  tliicknefs  of  their  fidesf 
and  fend  the  Blood  to  the  Arteries.;  and,  during  their  contraftion, 
they  are  thrown  by  the  dilatating  Auricles  againft  the  Ribs,  where 
the  ffroke  occafioned  by  the  Pull'e  of  the  Heart  may  be  felt. 

The  Arteries,  by  their  contradffile  power  and  elafticity,  fend 
the  Blood  fuddenly  to  the  Veins,  through  which,  by  the  united 
force  of  the  Ventricles  and  Arteries,  and  iikewife,  as  is  fuppofed 
by  fome,  by  a contraflile  power  of  the  Veins  and  preffure  of  the 
furrounding  parts,  it  is  driven  again  to  the  Auricles. 

In  its  coutfe  the  Blood  performs  a double  Circulation,— -one 
called  the  Leffer  or  that  through  the  Lungs; — the  other  called 
the  Greater,  ®r  that  through  the  Body. 

In  the  former  it  pafl'es  from  the  Right  Ventricle  to  the  Lungs, 
and  returns  to  the  Left  Auricle. — In  the  latter,  it  goes  from  the 
left  Ventricle  to  the  different  parts  of  the  Body,  ana  returns  to  the 
Right  Auricle. 

During  this  Circulation,  the  Auricles  and  Arteries,  and  the 
Ventricles  and  Veins,  a<EI  in  concert,  contrafting  and  dilating  at 
the  fame  time. 

UTe  of  the  Heart. -The  Heart  is  the  centre  of  the  Vafcu- 

lar  Syltem,  and  the  principal  agent  in  the  Circulation  of  the 
Blood. 

The  right  fide  of.  ihe  Heart  receives  the  Blood,  which  is  con- 
taminated in  paffing  through  the  Body,  and  fends  it  to  the  Lungs, 
where  it  is  purified  through  the  medium  of  the  Air. 

From  the  Lungs,  ihe  Blood,  now  purified,  is  returned  to  the 
left  fide  of  the  Heart  to  be  circulated  through  all  the  other  parts 
of  the  Body,  thereby  imparting  Nourifhment,  Growth,  and 
Strength  to  the  general  Syftem  ; being  found  all'o  to  be  the  fource 
of  Senfibility,  Irritability,  and  Motion,  and  Iikewife  of  the  Ani- 
mal Heat. 


OF  THE  LUNGS. 


The  Lungs  are  two  foft  fpongy  bodies,  which  occupy  by  much 
the  greater  part  of  the  Cavity  of  the  Thorax. 

They  completely  fill  the  two  bags  of  the  Pleura,  and  are  every 
where  in  contatt  with  the  parts  adjacent ; no  Air  intervening  be- 
tween them  and  the  Thorax. 

In  figure,  they  have  been  compared  to  that  of  the  Foot  of  an 
Ox,  with  the  back  part  turned  forwards  or,  their  fhape  cor- 
refponds  exaftly  with  the  infide  of  the  Thoiax,  being  rounded 
next  the  Ribs,  hollow  towards  the  Diaphragm,  and  irregu- 
larly flattened  and  depreffed  next  the  Mediaitinum  and  Heart. 

They  are  of  a reddifh  or  pink  colour  in  Children,  of  a light 
blue  or  greyifh  colour  in  Adults,  and  more  of  a purple  and  li- 
vid colour  in  Old  Age,  at  which  period  they  are  alfo  oblerved  to 
be  tinged  with  black  fpots,  proceeding  from  a matter  fecreted  in 
their  Subllance. 

They  are  joined  to  the  Neck,  by  the  Trachea;  to  the  Spine, 
by  the  two  Layers  of  the  Mediallinum,  which  ferve  them  as 
Ligaments  ; and  to  the  Heait,  by  the  Pulmonary  VelTels; — the 
relt  of  them  being  free  and  unconnected,  unlefs  an  adhefion  has 
taken  place  in  confequence  of  inflammation . 

They  are  divided  into  Right  and  Left  Portions,  or  Lungs, 
which  are  feparated  from  each  other  by  the  Heart  and  Mediaiti- 
num and  which  have  no  communication,  excepting  through  the 
Medium  of  the  Trachea. 

Each  of  the  Lungs  is  again  divided,  into  large  portions,  called 
Lobes,  which  facilitates  their  motion  and  the  dilatations  of  their 
Cells. 

Of  the fe  Lobes,  three  belong  to  the  Right  Lung,  correfpond- 
ing  with  the  larger  Bag  of  the  Pleura,  and  tnxso  to  the  left,  be- 
tween which  there  is  a Notch  or  Sinus,  occupied  by  the  Point  of 
the  Heart. 

Each  of  the  Lobes  is  fubdivided  into  many  fmaller  parts, 
termed  Lobules,  which  are  of  different  lizes,  anti  of  an  irregular 
angular  form. 

The  Lobules  dimlnifh  in  fize,  and  degenerate  at  laft  into  finall 
Vefclcs  or  Cells,  which  conftitute  a large  /hare  of  the  Lungs,  and 
•which  are  merely  vifible  to  the  naked  Eye. 

The  Cells  of  the  Lungs  are  purely  Membranous,  of  an  irregu- 
lar figure,  comprefled  and  clofely  connefted,  and  have  a free 
communication  with  each  other. 

Between  the  different  Lobes,  Lobules,  and  Cells,  a large 
quantity  of  common  Cellular  SubUance,  flefldtute  of  Fat,  is  in- 


85 


tcrpofed,  which  unites  and  (Lengthens  them,  and  allows  the 
Bjood-veffe'ls  to  be  minutely  dil'peried  over  them. 

The  Cells  of  :he  Lungs  have  no  communication  with  this, 
common  Cellular  Subffanre  ; for  when  Air  is  blown  into  it,  the 
Lobules  are  coinprefled  ; but  when  the- Air  is  blown  in  through 
a Bran.h  of  the  Trache-i,  the  Cells  are  again  iliffended,  and  tne 
Lobules  lecover  their  former  dimenuons. 

In  the  Fee. us,  the  Cells  are. empty  and  in  a collapfed  ftate  ; 
— but  as  icon  as  Respiration  begins,  they  become  diffended,  and 
continue  fo  during  life,  and  in  every  ftate  of  Refpiration,  and 
even  in  the  recently  dead  Body  : — But  if  an  opening  be  made 
into  the  Cavity  of  the  Thorax*  whether,  in  the, living  or  dead 
Body, — and  the  Air  in  this  or  in  any  other  way  admitted,  they 
immediately  co.lapfe  by  their  own  weight  and  e,iaftscitv,  the 
prelfure  of  the  air  being  then  the  fa  ne  on  the  outer  Surface  of 
the  Lungs,  and  inner  Surface  of  the  Trachea. 

The  Lungs  are  covered  by  .two  Coats,  an  External  or  Com- 
mon, and  an  Internal  or  Proper  one. 

The  External  o.  Common  Coat  is  a continuation  or  reflefljon  of 
the  Pleura,  is  extremely  thin,  butdenfe,  and,  like  the  other  parts 
of  tbe  Pleura,  is  found  to  polfefs  little  Sepfibiiity,  It  forms  a 
general  covering  to  the  Lungs,  but  does  not  enter  between  their 
different  Lobules. 

The  Internal  or  Proper  Coat  adheres  fo  firmly  to  the  former, 
as  to  appear  to  conffitute  part  of  its  Subffance.  It  not  only  co- 
vers the  Lungs,  but  infinuates  itfelf  between  their  Lobules,  and 
is  intimately  connected  with  their  Cellular  Subffance. 

Befides  the  Cells,  various  kinds  of  VefTels,  viz.  th tAir-vef- 
f els  or  Branches  of  the  Trachea,  Blood-'vejJ'els  and  Ahforbents,  to- 
gether with  fmall  Branches  of  Nerves,  enter  into  the  compoiition 
of  the  Lungs. 

Trachea. 

The  Trachea,  or  Afpera  Arteria,  fo  called  from  the  inequali-' 
•V  of  its  Surface,  and  from  its  conveying  Air,  begins  at  the  un- 
der put  of  the  Cricoid  Cartilage,  and  defeends  in  the  fore  part 
ot  the  Neck,  between  and  behind  the  Sterno-hyoid  and  Sterno- 
thyroid Mufcles. 

From  the  Neck,  it  naffes  into  the  Thorax,  vfrhere  it  is  fituated 
between  t!ie  Layers  of  the  upper-part  of  the  posterior  Media- 
ftsnnnj. 

Behind  the  Curvature  of  the  Aorta,  and  oppofite  to  tlife1 
thud  Vertebra  or  the  Th  rax,  the  Trachea  divides  into 'two 
Lateral  Branches,  termed  Bronchi,  from  the  Greek,  one  of  which 
goes  to  the  Right,  and  the  other,  which  is  the  longer  of  the  two' 
to  the  Left  Lung.  - . . 


Vo  L.  II. 


H 


86 


The  Bronchi  are  divided  into  Branches,  which  by  degrees  be- 
come fmallei-,  and  at  lad  terminate  in  the  Cells  of  the  Lungs, 
which  communicate  To  freely  with  each  other,  that,  upon  intro- 
ducing Air  into  any  of  thefe  Brandies,  a large  portion  of  the 
Lungs  may  be  inflated. 

The  Trachea  confifts  of  Cartilaginous  Rings,  about  fixteen  or 
eighteen  in  number,  which  give  (Length  and  firmnefs  to  it,  and 
preierve  it  conftantly  open  for  the  trammiffion  of  Air.  They  are 
incomplete  behind,  where  the  Trachea  is  formed  of  a foft  Elejhy 
Sub_ftar.ce , which  yields  to  the  Efophagus  in  the  time  of  Deglu- 
tition. 

Each  Cartilage  forms  a large  fegment  of  a circle,  about  a line, 
or  one-twelfth  of  an  inch  in  bre'adch,  and  one-fourth  of  a line  in 
thicknels. 

The  Cartilages  are  fituated  horizontally,  with  their  edges  op- 
pofed  to  each  ether,  fmall  fpact  s intet  veiling  between  them. 

They  are  united  to  each  other,  by  a Ligamentous  Subftance, 
which  is  lb  elaftic,  that  when  the  Lungs  are  taken  out  of  the 
Body,  it  draws  the  Cai  tilages  cloiely  together. 

At  the  upper  end  of  the  Trachea,  two  or  three  of  the  Cartila- 
ges are  frequently  joined  by  an  union  of  Subftance  ; but  below 
this,  they  are  perfedly  dift  nft  from  each  other. 

The  beginnings  of  the  Bronchi  have  the  fame  kind  of  Cartila- 
ges with  the  Trachea  ; but  after  they  enter  the  Lungs,  they  are 
broken  into  two  or  three  pieces,  which  go  completely  round  the 
Bronchi,  and  are  fo  conneded  to  each  other,  as  to  keep  the  Paf- 
fage  open  and  free  from  compiefiion. 

The  Trachea  has  feveral  Coats  entering  into  its  compofition, 
fomefor  (Lengthening  it,  others  for  giving  it  a certain  degree  of 
motion,  viz. 

A Cellular  Coat,  which,  in  the  Thorax,  is  coveted  by  the  Me- 
diaftinum. 

An  Elajlic  Ligamentous  Coat,  which  pafles  along  the  Trachea, 
and  alio  upon  the  different  Branches  in  the  fubftance  of  the 
Lungs,  adding  much  to  the  elafticity  of  thefe. 

A Mufcular  Coat,  placed  between  the  Cartilages,  and  in  the 
back-part  of  the  Trachea,  and  coinpofed  of  Circular  Fibres 
without,  and  Longitudinal  Fibres  within  ; — the  former  for 
ftraitening,  the  other  for  (hortening  the  general  Paffage. 

The  Longitudinal  Fibres  arecolleded  into  bundles,  which  are 
diftindly  feen  through  the  inner  Coat,  and  may  be  traced  con- 
siderably farther,  in  the  Subftance  of  the  Lungs,  than  the  Carti- 
lages. 

The  inner  fide  of  the  Trachea  is  lined  with  a very  Cafcular 
und  Irritable  Membrane,  continued  from  the  Mouth,  and  form- 
ing at  latt  the  extreme  Branches  of  the  Trachea,  which  terminate 
m the  Cells  of  the  Lungs. 


S7 


The  inner  Membrane  of  the  Trachea  is  every  where  perforated 
by  the  Duels  of  Mucous  Glands,  and  by  the  Mouths  of  the  Ex- 
hales:! Arteries,  the  former  pouring  out  Mucus  to  lubricate  the 
Lungs,  tne  other  the  Vapour  which  is  thrown  off  in  Perfpira- 
tion. 

Three  different  kinds  of  Glands  are  conneiled  with  the  Tra- 
chea,— the  Thyroid,  the  Tracheal,  and  the  Bronchial. 

The  Thyroid  Gland  has  its  name  from  its  connection  with  the 
Thyroid  Cartilage,  though  more  immediately  connected  with 
the  Trachea. 

It  is  a large  reddifh  mafs,  fi  uated  at  the  under  and  fore-part 
of  the  Larynx,  behind  the  Sterno-hyoid  and  Sterno- thyroid 
Mufcles . 

It  has  two  Lobes  placed  at  the  under  and  lateral  parts  of  the 
Larynx,  del'cending  a certain  way  upon  the  Trachea  and  Efo- 
phagus. 

fhe  Lobes  are  joined  by  an  intermediate  portion,  which  lies 
acrofs  the  upper  and  fore-part  of  the  Trachea, 

Sometimes  a Procels  from  the  middle  portion  afeends  between 
the  Sterno-hyoid  Mufcles,  and  is  loft  behind  the  Bafe  of  the  Os 
Hyoides. 

This  Gland  has  a Grandulous  appearance  within,  and  a vifeid 
Liquor  is  fometimes  obferved  in  it,  which  has  been  fuppofed  by 
Sabatier  and  others,  to  lubricate  the  parts  in  the  neighbour- 
hood. 

It  is  fupplied  with  large  Blood -veffels,  and  with  feveral 
Nerves,  from  thofe  of  the  Larynx  ; it  is  likewife  furniflied  with 
numerous  Lymphatics, — but  no  Excretory  Du£l  has  yet  been  ob- 
ferv£d  to  come  from  it  ; nor  is  its  office  yet  underftood. 

The  Tracheal  Glands  are  fmall,  but  numerous,  and  of  different 
fizes,  furrounding  the  Mufcular  Coat  of  the  Trachea,  and  its 
Branches  in  the  Lungs  ; the  largeft  of  them  are  placed  in  the 
Flefhy  Subftance  behind. 

From  each  of  thefe  Glands  a fmall  Du£I  iffues,  and  throws 
out  a Mucus,  to  defend  the  inner  Surface  of  tne  Trachea  from 
being  injured  i>y  the  Air,  or  by  the  extraneous  particles  which  it 
carries  along  with  it. 

The  Bronchial  Glands  are  placed  in  the  Cellular  Subftance 
round  the  under  end  of  the  Trachea  and  roots  of  the  Bronchi, 
where  thefe  penetrate  into  the  Subftance  of  the  Lungs. 

They  arc  of  various  fizes,  from  that  of  the  point  of  the  Lit- 
tle Finger  to  that  of  a Millet-feed,  and  have  a bluifh  or  black 
colour,  correfponding  in  a great  meafure  with  the  colour  of  the 
darkeft  pails  of  the  Lungs. 

They  were  formerly  confidered  by  many  Authors  as  fending 
Fluids  to  the  Trachea,  but  are  now  fufficiently  known  to  be  entire- 


83 


iy  ef  the  Lymphatic  kind, — the  Abforbents  of  the  Lungs  paffing 
through  them  in  their  way  to  the  Thoracic  Dufl. 

The  Trachea  is  furnifhed  with  Blood-<vc£els  from  the  Inferior 
Laiyngeals,  and  Nerves  hem  the  Recurrents  and  great  Sym- 
pathetic Pair. 

The  Trachea  ferves  to  convey  Air  into,  or  out  from  the  Cells 
of  the  Lungs,  during  Relpiration,  and  to  carry  off  the  Peiipir- 
able  Mattel  front  their  Arteries  in  time  of  Expiration. 

The  Blood-  Vejfels  tf  the  Lungs  confift  of  the  Pulmonary  and 
Bronchial  VeJJ'els  ; the  one  for  the  general  Circulation,  the  other 
proper  to  the  Lungs. 

Tlie  Pulmonaiy  Artery  arifes  from  the  top  of  the  Right  Ven- 
tricle, divides,  like  the  Trachea,  into  Right  and  Left  Branches, 
which  are  dilperled  through  the  lubltance  of  the  Lungs. 

The  minute  Blanches  tunning  in  the  common  Cellular  Sub- 
ftance,  form  at  lall  a Plexus  upon  the  proper  Cells,  fometimes 
called  Rete  Mirabile,  and  Rete  Vafculofum  Malpighii,  from 
which  that  Halitus  is  derived  which  is  expelled  by  the  Lungs  in 
Expiration. 

The  Pulmonary  Veins  are  commonly  obfetved  to  be  fmaller  in 
proportion  to  the  correTponding  Arteries,  than  Veins  are  to  Ar- 
teries in  other  parts  of  the  Body,  which  has  been  fuppofed  to  be 
owing  to  the  large  quantity  of  Fluids  expired. — They  join  into 
four  principal  Trunks,  which  terminate  in  the  Left  Auricle. 

The  Bronchial  Arteries  arife  by  tlnee  or  four  fmall  Branches, 
one  of  which  is  from  the  right  Superior  Intercollal,  the  reft'from 
the  Trunk  of  the  Aorta. 

They  aie  dilperled  upon  the  Bronchi  and  Bronchial  Glands, 
and  fubftance  of  the  Lungs  in  general,  and  are  found  to  com- 
municate with  the  Pulmonary  Artery. 

The  Bronchial  Arteries  are  fuppofed  to  ferve  for  the  nourifh- 
ment  of  the  Lungs  and  fecretion  of  the  Mucus. 

The  Veins  return  the  Blood  to  the  Vena  Azygos,  and  left  fu- 
per'or  Intercollal  Vein. 

The  Lymphatics  form  a Plexus  upon  the  Surface  of  the  Lurgs : 
—They  communicate  fieely  with  the  deep-fcated  Abfcrberiis, 
and  pafs  through  the  Bronchial  Glands. 

The  Nerves  of  the  Lungs  are  partly  from  the  great  Sympathe- 
tics,  but  chiefly  from  the  Eighth  Pair,  and  are  rather  fmall  in 
proportion  to  the  bulk  of  the  organ  on  which  they  are  dilperled. 

The  Lungs  ferve  the  general  purpofe  of  Refpiration,  which 
con  fills  of  Indication  and  Expiration,  or  the  paflage  of  the  Air 
inlu  or  out  from  the  Lungs  by  the  alternate  dilatation  and  con- 
fiaffion  of  the  Thorax. 

I/ifpiration  is.  performed  in  confequence  of  the  Thorax  being 
dilated  by  the  aftion  chiefly  of  the  Diaphragm  and  In  ei  coital 
Mufcles  ; the  Lungs,  which  are  paffive,  and  in  contact  with 


89 


the  Thorax,  following  it,  and  the  Air  rufhing  into  the  Trachea 
by  its  own  gravity. 

Expiration  is  performed  in  confequence  of  a relaxation  of  the 
Mufcles  which  dilate  the  Thorax, — of  the  action  of  the  Abdo- 
minal and  a few  other  Mufcles, — of  the  elaftic  ty  of  the  C irtila- 
ges  of  the  Ribs,  and  likewife  of  the  Lun  . s,  by  which  the  Cavity 
of  the  Thorax  is  diminifhed,  and  the  Air  is  expelled  from  the 
Lungs. 

Upon  the  alternate  (dates  of  Infpiration  and  Expirat'on,  de- 
pend the  formation  of  the  Vo  ce,  the  fenfation  of  Smell,  and  all 
the  other  functions  of  the  Body  : but  the  g eat  and  principal 
office  of  the  Lungs,  which  was  formerly  fuppofed  to  be  that  of 
cooling  the  Blood  over-heated  by  friction,  is,  during  Infpda- 
tion,  to  receive  from  the  Atmofphere  pure  At,  upon  wbicn  the 
principle  of  heat  and  life  Depends;  and,  during  Expiration,  to 
carry  off  an  impure  Air,  which  is  noxious  to  An  mal  Life. 

According  to  late  experiments,  it  appears,  that  the  Venous 
Blood  parting  to  the  Lun;s,  of  a dark  red  or  purple  colour,  is 
charged  with  Carbon  or  Charcoal,  and  Hydrogen,  or  Inflamma- 
ble Air; — that  while  crcularing  upon  the  Bronchial  Cells,  one 
part  of  the  Oxygen,  or  V.tal  Air,  contained  in  the  common  Air 
which  has  been  infpired,  Unites  with  the  Carbon  and.  lydrogen, 
ant  forms  Fixed  Air  and  a Watery  Hal.tus,  whi.b  are  earned 
off  by  Expiration  ; — that  another  part  of  the  Oxygen  is  imbibed 
by  the  Blond,  which,  in  confequence  of  thef'e  changes,  returns 
from  the  Lungs,  of  a florid  red  colour,  and  full  of  heit  in  a 
latent  (late,  which  becomes  fenlible  in  the  coilffe  of  the  general 
Circulation,  and  is  diffufed  over  the  different  parts  of  the  Body  ; 
and,—  hat  the  Blood  thus  changed  alfo  affords  a St, nidus  to  the 
Arteries,  and  promotes  the  different  Secretions. 


Esophagus. 

• iHe  Esophagus,  called  aifo-  Gala  or  Gullet , derives  its 
name  from  can ying  whet  is  eaten  into  the  Stomach. 

It  is  a tieftiy  Canal,  which  begins  fr,  m t ie  nferior  part  of 
tne  Pnarvnx,  dec  end  along  the  Neck,  and  through  the  Thorax, 
following  nearly  t ie  direaion  of  the  Spine 

It  is  tituated  between  the  Trachea  and  Vertebra  ; and  in  the 
Thorax,  ,t  proceeds  behind  the  Bafe  of  the  Heart,  and  between 

..e  -ayeis  of  the  Polterior  Me.diaihnum,  fioin  which  it  receives 
a lateral  covering. 

Soon  after  entering  the  Thorax,  it  makes  a flight  turn  to  the 
r-ht,  and  partes  down  upon  the  fore  and  right  fide  , f the  Aorta, 
b)  w h i n tney  are- prevented  fr,  m injuring  each  other. 

;'S  l>roSre!s>  inclines  more  forwards  and  to  the  left  fide: 
and  aoom  the  Ninth  Vertebra  of  the  Thorax,  it  perfura  es  the 

anJ  teiini—  - “PI- 


Vol.  II.  H 2 


so 


It  has  fevrral  Coats  proper  to  it,  the  ft,  ft  f which  is  Cellular, 
and  conn  £ls  it  to  the  adjacent  par  s. 

The  ffcond  Coat  is  Mufcular,  and  is  fonsetimes  termed  Vagi- 
nalis GuLe. — It  con  inis  ot  two  Layei  s ■,  the  external  of  which 
has  thick,  lining,  longitudinal  F.bres  ; the  internal  is  forme  I of 
Circular  and  tranfverfe  Fibres,  and  is  thinner  than  the  former. 
— The  outer  Layer  is  fitted  for  fhorten  ngand  relaxing,  and  the 
inner  for  contracting  the  Canal,  during  Deglutition. 

The  third  Coat  is  termed  Nervous,  but  is  properly  Cellular, 
being  formed  of  loofe  Cellular  Subltance,  which  councils  the 
Mufcular  to  the  Inner  Coat. 

The  Inner  Coat  is  continued  from  the  Lining  of  the  Mouth  : 
It  confilts  cl  many  longitudinal  Plica1  or  Folds,  which  are 
fcarcely  vifible  when  the  Efophagus  is  dilated,  and  is  funufhed 
with  numerou  Foramina,  which  difeharge  a Mucus  for  lubri- 
cating the  paflage,  anil  facilitating  Deglutition. 

The  Arteries  of  the  Efophagus  are  Branches  of  the  Inferior 
Laryngeal',  which  fupply  the  Cervical  part  of  it,  and  Efopha- 
geils  and  Branches  of  the  Bronchials,  which  are  derived  fiom 
the  Aorta  Defcendens,  and  fupply  the  Thoracic  part  of  it. 

The  Veins  go  to  >he  inferior  Laryngeals,  to  the  Vena  Azygos, 
and  left  Superior  Jut:  recital  Vein. 

i he  A'olbrbents  are  numerous,  and  intermix  with  thofe  of  the 
Heart  and  Lungs. 

The  Nerves  are  chiefly  from  the  Eighth  Pair. 

TTe  ufe  of  tiie  Efophagus  is,  to  receive  the  Aliments  from  the 
Pharynx,  and  convey  them  to  the  Stomach. 

Thoracic  Duct. 

The  Thoracic  Duct  is  a i mall  Membranous -like  Canal, 
fttuated  in  tile  back  part  of  the  Thoiax,  and  is  the  principal 
Tiunk  of  the  Abforbent  Syflem. 

It  begins  upon  the  thud  Vertebra  of  the  Loins,  and  paffes  be- 
hind the  Aoita,  eroding  obliquely  from  left  to  right,  till  it  gets  to 
the  r'glit  fide  of  iha  Artery. 

Upon  the  fidl  Lunibai  Veitebir,  1 foims  an  Oval  Sac,  term- 
ed Receptaculum  Chyli , wh  ch  is  , i ced  behind  the  Right  C>  us 
of  toe  Diaphragm,  and  a iiitle  higher  than  the  Right  Renal 
Artery. 

The  Du£l  afterwards  paffes  between  the  Cruiaof  the  Dia- 
phr  gm,  and  allends  in  the  Thorax,  on  the  anterior  part  of  the 
Spii  e,  : etween  the  Layers  of  the  Pofterior  Mediallinuro,  on  the 
right  fide  of  the  Aorta,  and  between  it  and  the  Vena  Azygos. 

It  erodes  behind  the  upper  part  of  the  descending  Aorta,  and 
emerges  fiom  the  Thorax,  to  reach  the  under  part  of  the 
Neck. 

In  the  Neck,  it  paffes  behind  the  Internal  Jugular  Vein,  and  a 
little  higher  than  the  Subclavian. 


91 


It  then  turns  downwards,  forming  an  Arch,  which  termi- 
nates in  the  upper  part  of  the  Angle,  between  the  Internal  Jugu- 
lar and  Subclavian  of  the  Left  Side. 

The  Thoracic  Duft  receives  the  Chyle  from  the  L:.£leals,  and 
Lymph  from  the  Lymphatics,  and  difcharges  thefe  into  the  red 
Veins. 

»^»oooooooo  @00000000  **■- 

OF  THE  ABDOMEN. 


The  Abdomen  or  Belly  extends  from  the  Thorax  to  the  under 
part  of  the  Trunk. 

It  is  bounded  above,  by  the  Diaphragm,  and  the  Bones  to 
which  that  Mufcle  is  fixed;  below,  by  the  Pelvis;  behind,  by 
the  Lumbai  Vertebrae  and  Mufcles  of  the  Loins;  anteriorly,  by 
its  Proper  Mufcles  ; and  laterally,  by  the  Falfe  Ribs,  Ofia  Ilii, 
and  Mufcles  connected  with  thefe; — all  of  which  have  been  de- 
fcribed  in  their  places. 

It  is  diftin0uiflied  into  three  Di-vi/ions  or  Regions,  termed  Up- 
per, Middle,  and  Under  Region  ; each  of  which  is  fubdivided 
into  three  others. 

The  Upper  Region  begins  oppofite  to  the  Carfilapo  Enfiformis, 
at  a fmall  depreffion  called  Scrobiculus  Cordis,  or  Pit  of  the  Sto- 
ma. h,  and  extends  to  about  a hand-breadth  from  the  Umb.licus 
or  Navel. 

The  mddle  of  this  Region  is  termed  Epigajirium,  or  under 
part  of  the  Belly,  and  the  two  lateral  paits  Hypochondria,  from 
their  lying  under  the  Cartilages  of  the  Falfe  Ribs. 

The  Middle  Region  occupies  an  equal  distance  above  and  be- 
low the  Umbilicus. — I'he  middle  part  of  it  s called  the  Umbilical 
and  its  lateral  pirts  the  Lumbar  Regions  or  Loins. 

The  Under  Region  begins  where  the  middle  one  terminates,  cr 
at  a line  drawn  between  the  fuperior  anterior  Spinous  Procefl'es 
of  the  Oifa  Ilii,  and  forms  in  the  middle,  the  HjpogaJlrium  or 
bott<  m T the  Belly  ; and  at  the  Tides,  the  Iliac  Regions. 

The  Abdomen  is  covered  on  the  outfide  bv  the  common  Integu- 
ments, and  l’ned  within  by  the  Peritoneum,  in  the  manner  the 
Thorax  is  lined  by  the  Pleura,  but  without  being  divided  by  the 
intervention  of  a Partition. 

The  Abdomen  contains  the  Cbylopoetic  and  Afjiftanl  Chylopoeiic 
Fife  era  or  Organs  of  Digefion , — the  Organs  of  Urine,  and  part  of 


92 


thofe  of  Generation,  with  the  Vefj'els  and  Nerves  which  belong, 
fome  of  them  to  thefe  Vifcera,  and  others  to  the  lower  parts  of 
the  Body. 

The  Cbylopoelic  Vifcera  comprehend  the  Stomach,  which  is  fi- 
tuated  in  the  Upper  and  left  part  of  the  Abdomen, — the  Intefines, 
which  fill  the  greater  part  of  it, — and  the  Membranes,  termed 
Omenta  and  Mefentery,  which  are  conne&ed  with  thefe. 

The  AJJiflant  Cbylopoetic  Vifcera  conlift  of  the  Liver,  which  is 
placed  in  the  upper  and  right;  of  the  Spleen,  which  is  fituated 
in  the  upper  and  left  fide  of  the  Abdomen  ; — and  of  the  Pancre- 
as, which  lies  undei  the  Stomach. 

Of  the  Organs  of  Urine,  the  Kidneys  are  placed  in  the  back- 
part  of  the  Abdomen,  and  the  Bladder,  with  iome  of  the  Organs 
of  Generation  in  the  Pelvis. 

Peritoneum. 

The  Peritoneum,  named  from  its  being  ftretched  or  fpread  a- 
round  the  Bowels,  is  a firm  but  fimple  Membrane,  by  which  the 
Abdominal  Vifcera  are  furrotinded,  and  pai  tly  fupporled. 

Its  External  Surface  is  rough  and  Cellular,  and  clofely  con- 
nected with  the  parts  to  which  it  belongs. 

The  Internal  Surface  is  remarkably  fm.ooth,  and  lubricated 
by  a Liquor  which  is  exhaled  from  its  own  VefTels. 

It  is  very  elaftic,  and  admits  of  great  extenfion,  as  happens 
in  Geilation,  Corpulency,  or  Afcites;  but,  upon  the  caufes  of 
extenfion  being  removed,  it  returns  to  its  former  dimenfions. 

It  lines  the  Diaphragm,  paffes  downwards,  adhering  firmlvto 
the  Abdominal  Muicles, — lines  the  containing,  and  covers  the 
contained  parts  of  the  Pelvis,  from  which  it  is  rePitCIed  in  the 
bar  k-part  of  the  Abdomen,  lining  its  Mu  cles,  and,  by  its  re- 
duplications, covering  the  Bowels  and  great  Blood- vefl'els  of  that 
Cavity; — thorp  h,  (inCtlv  ipeaking,  the  Abdominal  Vifcera  may 
be  fa i d to  lie  0.1  the  outfide  of  it. 

In  its  pafta.e  from  one  Bowel  to  another,  it  forms  doublings 
which  f'erve  as  Ligaments  to  fix  them  to  each  other,  and  like- 
wife  to  the  Body. 

It  gives  a general  covering  to  mod  of  the  Bowels,  a partial 
one  to  a few,  and  to  thofe  which  are  deep-feated,  and  projecl  lead, 
■a  (fill  more  partial  covering. 

It  forms  a large  Sac,  tlu  pnfteripr  part  of  which  adheres  firm- 
ly t > the  differt;  t Vifcera,  and  the  anterior  to  the  Ah  loin  nal 
MolCies  ; — he  par  lining  the  Abdomen  being  merely  in  contact 
with  ns  Co  tents,  and  allowing  a (mail  degree  of  motion. 

Til  Cellular  Sub.. ance,  on  the  Ex'.ei  nal  Surface  of  tins  Mem- 
brane, in  not  every  whe.  e of  equal  thicknefs,  being  m fome  parts, 
as  upon  lilt  Bowels,  remuka  ly  thin;  in  ethers,  as  over  the 
. Kidneys,  filled  with  a cunfiderable  quantity  of  Fat. 


93 


The  Cellular  Subftance  forms  various  Precedes  or  productions, 
feme  of  which,  as  thole  on  the  Spermatic  Cord's,  pafs  through 
Foramina,  to  be  connected  with  the  neighbouring  parts  ; and  the 
Proceffes  are  fent  off,  without  affeCting  the  Internal  Membrane, 
the  one  not. accompanying  the  other. 

The  Fejfels  and  Nerves  of  the  Peritoneum  are  from  thofe  which 
fuppjy  the, contiguous  parts  ; its  Veflels,  however,  are  not  very 
mimetous;  neither  does  it  p off.  is  much  S enlibi  1 i ty  when  free 
from  difeafe. 

The  Arteries  come  from  the  Internal  Mammary,  Epigaltric, 
Inferior  Inte,  coftai,  Lumbar,  Sacral,  and  lleo  lumbar  Arteries, 
and  from  thofe  whica  fupply  the  Abdominal  VilCeva. 

The  Veins  have  the  fame  courle,  bear  the  fame  names,  and  in 
general  pals  to  the  Inferior  Cava. 

The  Abforbents  are  numerous,  and  run  chiefly  to  the  Iliac  and 
Lurubar  Plexus. 

. ..The  Nerves,  which  are  few  in  number  and  fmall,  are  from 
the  Inferior  Dorfai,  the  Lumbar,  the  Great  Sympathetic  and 
Sacral  Nerves. 

The  ufe  of  the  Peritoneum  is  to  line  and  ftrengthen  the  Cavity 
of  the  Abdomen  ; to  inclofe  and  aflift  in  fuppprting  its  different 
Vifcera  ; to  furnilh  molt  of  them  with  an  External  Coat ; to  con- 
ned them  to  the  Body,  and,  by  its  fmoothnefs  and  fiipperinefs, 
to  prevent  the  effeds  of  FriCiion. 

Upon  the  outfid,e  of  the  Peritoneum  are  Four  White  Lines,  or 
fmall  Cords,  three  of  which  are  Veflels  in  the  Fcetus,— one  of 
them  a Vein,  and  two  of  them  Arteries  ; the  fourth  is  the  Ura- 
chus.— In  the  Adult,  they  are  fhrivelled  up,  and  ferve  as  Liga- 
ments, the  Vein  forming  the  round  Ligament  of  the  Liver,  the 
three  other  Cords,  foiming  Ligaments  of  the  Bladder. 


STOMACH. 


Til  E Stomach  is  a large  Bag  or  Refervoir,  fituated  obliquely 
acrofs  the  upper  and  left  part  of  the  Abdomen,  in  the  left  Hy- 
pochondriac and  Epigaftric  Regions. 

It  is  turned  downwards  and  fo.  wards,  fo  as  to  form  an  angle 
wtth  the  Efophagus,  the  angle  becoming  more  confpicuous,  ac- 
cording to  the  diiftenfron  of  the  Stomach. 

I he  right  part  of  the  Stomach  is  fituated  under  the  left  part  of 
the  Liver,  the  reft  of  it  is  placed  immediately  under  the  Dia- 
phragm, its  extremity  being  in  coiitaft  with  the  Spleen. 

The  Stomach  is  long,  round,  and  tapering,  acd  has  beeo 
compared  in  fliape  to  the  Bag  of  a Bagpipe. 


94 


The  Cize  is  in  proportion  to  the  quantity  of  Aliment  it  has 
been  accuftomed  to  receive,  and  therefore  is  commonly  larger  in 
Men  than  in  Women. 

it  has  a Labge  and  Small  Extremity , ah  Upper  and  Under  Sur- 
face, a Great  and  Small  Curvature,  a kept  and  Right  Orifice , 
and  confifts  of  feveral  Layers  or  Coats. 

The  Large,  called  alfo  the  Left  Extremity,  is  fituated  in  the 
left  fide  of  the  Abdomen,  and  is  confiderably  higher  than  the 
Tight. 

The  Upper  Surface  is  turned  towards  t he  Diaphragm,  the  Un- 
der towards  the  Inteftines; but  when  the  Abdomen  s Hid  o- 

pen,— unlefs  the  Stomach  be  conliderabiv  d i (tended , — the  Supe- 
rior Surface  becomes  anterior,  and  the  Inferior  Surface  poitcrior. 

The  Large  Curvature  is  turned  obliquely  forwards  and  down- 
wards towards  the  Abdominal  Mufcies,  and  extends  from  one 
Orifice  to  the  other. 

The  Small  Curvature  is  oppofed  to  the  other,  and  turned 
backwards  and  upwards,  towards  the  Spine,  extending  alfo  be- 
tween the  two  Orifices. 

The  Orifices  are  next  the  Small  Curvature.  The  left  is  termed 
Cardia,  or  Os  Ventriculi,  or  Upper  Orifice  of  the  Stomach. — It 
is  oppofed  to  the  Spine,  at  a little  diftance  from  it,  and  is  for- 
med by  the  termination  of  the  Efophagus.' — It  allow*  a free  Paf- 
fage  for  the  Food  into  the  Stomach,  the  return  ol  which  is  pre- 
vented by  the  Angle  formed  by  this  part  of  the  Stomach,  and 
by  the  Flefhy  Parts  of  the  Cardia,  and  of  the  Diaphragm  in 
which  it  is  fituated. 

The  Right,  or  Inferior  Orifice,  is  commonly  termed  Pylorus 
from  its  office  as  a Porter. 

It  is  fituated  under  the  fmall  Lobe  of  the  Liver,  a little  to 
the  right  fide  of  the  Spine, — is  turned  more  forwards  than  the 
Cardia,  and  is  confiderably  lower,  but  rifcs  in  proportion  to  the 
diftenfion  of  the  Stomach. 

The  Stomr.ch  is  conneXed  by  the  Cardia  to  the  Efophagus,-— 
by  the  Pylorus  to  the  beginning  of  the  Inteftines, — by  the  Peri- 
toneum and  Blood-vefi'els  to  the  Spleen, — and  by  a refleXion  of 
the  Peritoneum  to  the  root  of  the  Liver  and  to  the  great  Intef- 
tines. 

The  Strufiure  of  the  Stomach  is  in  general  fimilar  to  that  of 
the  Efophagus,  of  which  it  is  a kind  of  Expanfibn. 

The  Coats  uf  the  Stomach  are  four  in  number. 

The  firft  or  External  Coat,  called  alfo  Peritoneal,  is  a Reflexi- 
on of  that  part  of  the  Peritoneum  which  comes  from  the  root  of 
the  Liver. 

It  ftrengthens  the  Stomach  ; by  its  fmoothnefs  it  diminifhes 
the  efteX  of  FriXion,  and  poffeffing  few  Nerves  or  Blootl-vefiels, 
it  is  not  very  fufceptible  of  pain  or  inflammation. 


95 


The  Cellular  Subftar.ee  under  the  Peritoneal  Covering,  is  def- 
cribed  by  fonie  Authors  as  a diltincl  Co -it,  called  Tunica  Cellu- 
lofa  Ruyfchiana  ; — but  ought  not  to  be  numbered  among  the 
Coats  of  the  Stomach. 

The  Second  or  Mufcular  Coat  is  ccmpofed  chiefly  of  two 
Planes  of  Fibres  variously  dilpofed. 

The  External  Plane  is  Ion . itudinal,  extends  from  the  longi- 
tudinal Fibres  of  the  Efophagus,  and  follows  the  f.  me  general 
courfe  with  that  of  the  Stomach  from  the  Great  to  the  Small  Ex- 
tremity. 

Upon  each  fide  of  the  Small  Curvature,  the  longitudinal  Fi- 
bres form  a thick,  ftrong,  Mufcular  Band. 

The  fecond  Plane  is  chiefly  tranfverl'e  or  circular,  and  confi- 
derably  thicker  and  ftronger  than  the  other. 

Its  Fibres  are  interfered  by  many  lmall,  whj*e,  Tendinous- 
like  Lines  ; — thefe,  however,  are  in  a great  meafure  formed  of 
that  Cellular  Subftance  by  which  the  rwo  Coats  are  united. 

The  Mufcular  Coat  affifts  in  the  Digeftion  of  the  Food,  by 
giving  a gentle  motion  to  the  Stomach,  accordin  ; to  the  direflion 
of  its  Fibres,  the  one  fet  fhortening,  the  other  rendering  it  nar- 
rower. 

The  Pylorus  is  formed  by  a doubling  of  the  two  inner  Coats, 
which  project  into  the  Pafface  between  the  Stomach  and  Intef- 
tine,  and  contain  a Ring  of  Mufcular  Fibres,  which  form  a 
Sphincter,  called  Sphincter  Pylori. 

This  lublt2nce,  by  contrailing,  prevents  the  gre  (Ter  ind  gefted 
parts  of  the  Aliment  from  efcaping,  and,  by  dilating,  allows 
the  Pulpy  digefted  part  to  pals  to  the  Inteftines. 

The  Third.  Coat , commonly  called  Nervous,  but  properly  Cel- 
lular, confifts  of  a large  quanfty  of  fine  Cellular  Subftance, 
without  Far,  and  is  intermixed  with,  and  fupported  by  fmall 
Aponeurotic  like  Filaments,  which  crofs  each  other  obliquely, 
but  which  are  alfo  of  a Cellular  nature. 

This  Coat  ftrengthens  the  Stomach,  and  allows  the  Veflels  to 
be  diftributed  to  the  Inner  Coat,  with  which  it  is  intimately  con- 
nefled. 

The  Fourth  or  Inner  Coat,  called  alfo  Villous,  from  its  refem- 
blance  to  Velvet,  is  continued  from  the  Inner  Coat  of  the  Eio- 
phagus,  but  is  much  more  Villous. — It  is  formed  of  fine,  fhort, 
prominent  Villi,  which  are  crowded  with  Small  Veflels,  fome  for 
furnifhing  a Mucous  Liquor  to  the  Stomach,  others  for  abloibing 
a portion  of  the  thinner  part  of  the  Food. 

The  two  laft  Coats  are  more  extenfive  than  the  reft,  and  form, 
upon  the  inner  part  of  the  Stomach,  many  doublings,  termed 
Ruga,  the  greater  number  of  which  run  in  a waving  tranlverfe 
direflion,  and  are  afterwards  divided  Into  a fort  of  Net-vuork , 


96 


Near  the  Orifices,  however  efpecially  towards  the  upper  one,  they 
run  more  in  a longitudinal  direflion,  and  have  a radiated  appear- 
ance at  the  Cardia. 

The  Rugae,  like  the  Plicae  of  the  Efophagus,  are  molt  diftimft 
when  the  Stomach  is  empty  ; — when  full,  they  are  much  lefs 
evident. 

They  admit  of  diftention  without  endangering  the  VefTelS  and 
Nerves  difperfed  in  them,  and  aflift  a little  in  detaining  the  Ali- 
ment till  properly  digefted. 

From  the  Inner  Surface  of  the  Stomach  a Liquor  iffues,  which 
is  found  to  approach' to  the  nature  of  Saliva,  and  is  termed  Gaf-. 
trie  Juice. — This  was  formerly  fuppofed  to  come  from  Glands 
feated  in  the  Third  Coat,  but  is  now  more  frequently  cOnfideVed 
as  a Secretion  from  the  Aiteries  of  the  Stomach,  no  Glands  be- 
ing evident  there,  at  lead  in  the  found  (late  of  this  Vifcus. 

The  Arteries  of  the  Stomach  aie  derived  from  the  Coeliac 
Artery.  They  confift  of  the  Superior  Gaftric,  which  fupplies  the 
place  next  the  final!  Curvature  • the  Right  Infer  ior  Gaftric,  which 
is  a bianch  of  the  Hepatic;  the  Pyloric  Arteres,  which  are 
final!  branches  from  the  Gaftrics  and  from  the  Hepatic  ; and  of 
the  Left  Gaftric  and  Arteriae  breves,  which  are  branches  of  the 
Splenic  Artery. 

The  Veins  have  the  fame  names,  and  nearly  the  fame  courfe 
with  the  Ai  teries.  'J  he  whole  of  them  terminate  in  the  Vena 
Port®. 

The  Abforbents  of  the  Stomach  are  numerous  and  large.  They 
pafs  through  final!  Glands  fituated  upon  the  Curvatures,  and  go 
afterwards  to  the  Thoracic  Du£t. 

They  appear  to  carry  Lymph  only,  no  Chyle  having  been  dr 
tested  in  them,  evur  in  cates  where  the  Lafteals  were  found  full 
of  it. 

The  Nerves  are  chiefly  from  the  Eighth  Pair,  and  partly  from 
the  Gi eat  Sympathetics,  and  are  moft  numerous  upon  the  Car- 
dia. 

The  Stomach  receives  the  Food  from  the  Efophagus,  and  af- 
terwards prepares  it,  by  digeftion,  fur  the  Inteftir.ss. 

The  digtftion  of  the  Food  in  the  Stomach  is  found  to  be  efrer. 
ted, — by  Trifure,  which  is  performed  by  the  motions  of  the 
Stomach  and  furr minding  Mtifcles, — by  dilution, — by  a partial' 
fermentation. — but  chiefly  by  the  action  of  the  Gaftric  Juice  Li- 
ving as  a Menltruum. 


97 


INTESTINES. 

The  InteJHnes  eonfift  of  a long  Cylindrical  Canal,  which  be- 
gins at  the  Inferior  Orifice  of  the  Stomach,  and,  after  winding 
in  various  directions,  terminates  in  the  Anus. 

In  general  they  are  about  fix  timesthe  length  of  the  Body  to 
which  they  belong  ; though,  in  a perlon  of  fhort  Ifature,  the  pio- 
portional  length  of  the  Inteftines  is  greater,  and  vice  ve<fa. 

They  occupy  a large  part  of  the  Abdomen,  and  are  connected 
to  the  Body  through  their  whole  extent,  by  a doubling  of  the 
Peritoneum.  . 

On  account  of  the  inequalities  of  their  fize,  they  are  divided  in- 
to Small  and  Large  Intelfines,  and  each  of  thefe  is  fubdivided  in- 
to others. 

Small  Intestines. 

The  Small Intejlines  are  fmooth  on  their  outer  Surface,  and  of 
a tapering  form,  becoming  gradually  Ids  in  their  diameter  from 
their  upper  to  their  under  extremity,  and  are  divided  into  the 
Duodenum , Jejunum,  and  Ilium. 

The  Duodenum,  fo  called  from  its  being  about  twelve  fingers- 
bneadth  in  length,  begins  at  the  Pylorus,  and  makes  a fhort 
turn  upwards  and  backwards,  by  the  Neck  of  the  Gall-bladder, 
to  which  it  is  contiguous,  having  the  Anterior  Layer  of  the 
Omentum  fixed  to  its  inferior  part,  and  the  Omentum  Minus  to 
its  oppofite  fide. 

It  then  palTes  obliquely  downwards  and  to  the  right  fide,  before 
the  great  VefTels  which  go  into  the  Liver,  and  likewiib  before  the 
.Renal  Artery  and  Vein,  included  in  the  Ceilular  Subftauce  of 
the  Mefocoion. 

Oppofite  to  the  under  part  of  the  Kidney,  it  makes  a turn  to 
the  left  fide,  where  it  is  lodged  in  the  common  root  of  the  Me- 
focoion and  Melentery,  and  receives  into  its  back-part  the  ends 
of  the  Biliary  and  Pancreatic  Duds,  and  goes  over  the  Aorta  and 
Vena  Cava,  oppofite  the  laft  Vertebra  of  tiie  Back. 

In  palling  acrofs  thefe  VefTels,  it  is  involved  in  the  root  of  the 
Mefentery,  and  afeends  a little  t:  1 1 it  gets  to  the  left  fide  of  the 
Spine,  where  it  perforates  the  common  root  of  the  Mefentery  and 
Mefocoion,  and  makes  a turn  forwards,  where  it  obtains  the 
narpe  of  Jejunum. 

The  Jejunum  fo  named  from  its  being  commonly  more  empty 
than  the  other  Inteftines,  in  confequence  of  the  thinner  parts  of 
its  Contents  being  fooner  abforbed,  begins  at  the  laft  turn  of 
♦he  Duodenum,  aud  forms  numerous  Convolutions,  which  run  in 
all  directions,  and  are  fituated  in  the  upper  part  of  the  Umbili- 
cal Region. 


VOL.  II. 


I 


98 


The  Ilium , named  from  its  numerous  Turns,  begins  where 
the  Jejunum  terminates,  or  where  the  Internal  Plicae  become  lefs 
confpicuous,  and  is  diftinguifhed  externally  from  that  Gut,  by 
being  fmaller,  thinner  in  its  Coats,  and  paler,  and  from  its 
forming  about  three-fifths  of  the  length  of  the  two  Inteftines. 

The  Ilium,  like  the  Jejunum,  forms  many  Convolutions, 
which  are  fituated  on  the  under  part  of  the  Umbilical  Region,  and 
extend  as  far  as  the  Hypogaftric  and  Iliac  Regions,  and  not  un- 
frequently,  efpecially  in  Women,  into  the  Cavity  of  the  Pelvis. 

It  furrounds  the  lateral  parts  of  the  Jejunum,  and  is  fupport- 

by  the  Offa  Ilia;  and,  the  laft  turn  of  the  Gut  parting  acrofs 
towards  the  upper  edge  of  the  Right  Os  Ilium,  it  terminates  by 
a Valve  in  the  left  fide  of  the  beginning  of  the  Colon. 

Through  the  whole  of  this  couife,  the  Jejunum  and  Ilium 
are  fixed  to  the  Spine  by  a continuation  of  the  Mefentery. 

Great  Intestines. 

The  Great  Intejlines,  like  the  Small,  form  one  continued  Ca- 
nal, which  tapers  from  its  upper  to  near  its  under  extremity  ; 
but  differ  from  them  in  being  confiderably  larger,  fhorter,  and 
flraighter,  and  in  being  irregular  in  their  Outer  Surface,  and 
tacked  up  into  Cells,  having  beficles  many  Precedes  depending 
from  them,  termed  Appendiculce  Pinguidenofa? . 

Like  the  Small  Inteftines,  alfo,  they  aie  divided  into  three 
parts,  termed  Cacum,  Colon,  apd  Re  Sum. 

The  InteJUnum  Cacurn,  or  Blind  Gut,  forms  a round  fhort  Bag, 
only  about  three  or  four  Fingers-breadth  in  length,  and  nearly 
the  fame  in  diameter.  The  Caecum,  properly  fo  called,  is  that 
part  of  the  Inteliine  which  lies  under  the  Iniertion  of  the  Ilium, 
through  frequently  the  dilated  beginning  of  the  Colon  is  diftin- 
gui  filed  by  the  fame  name. 

It  is  fituated  in  the  Right  Iliac  Region,  retting  on  the  Cavity 
of  the  corrcfponding  Os  Ilium,  at  the  under  end  of  the  Right 
‘Kidney,  and  is  concealed  by  the  laft  Convolutions  of  the  Ilium. 

The  bottom  of  it  is  turned  downwards,  and  forms  a fhut 
Sac,  the  mouth  of  which  is  turned  towards  the  Colon,  and  may 
be  confidered  as  forming  the  Ceecum  Caput  Coli. 

At  the  poftei  ior  and  left  fide  of  the  Caecum,  there  is  a fmall 
Proeefs,  about  the  fame  length  with  the  Caecum  itfelf,  but  the 
diameter  not  larger  than  that  of  a Goofe-quill,— termed  Appen- 
dix' Vermiformis,  from  its  refemblance  to  an  Earth-worm,  and 
Appendix  Ca-ei,  from  its  connection  with  the  Caecum. 

It  is  convoluted,  and  fixed  by  its  fides  to  the  Caecum. 

It  has  two  extremities,  one  of  which  is  impervious,  the  other 
®pens  obliquely  into  the  back-part  of  the  Caecum. 

The  Colon,  fo  called  from  the  Greek,  is  by  much  the  longeft 
of  the  Lar«e  Inteftines.  It  encircles  the  Small  Guts,  and  is  con- 
tiguous to  mod  of  the  Abdominal  Vifcera, 


It  is  a continuation  of  the  Caecum,  beginning  at  the  termina- 
tion of  the  Ilium. 

It  attends  in  the  Right  Lumbar  Region,  over  the  Kidney  of 
that  fide  to  which  it  is  conne6ted. 

From  the  Kid  ;ey,  it  puffes  forwards,  and  erodes  the  Abdo- 
men in  the  Epigalcric  and  Hypochondriac  Regions,  connected  to 
the  Duodenum,  under  the  name  of  Great  Arch  of  the  Colon, 

Theri  ,ht  portion  of  the  Great  Arch  is  tnuated  under  the  Li- 
ver and  Gall-bladder,  which,  after  death,  commonly  tinges  part 
of  it  and  of  the  Duodenum  with  Bile. 

The  left  portion  is  lituated  under  the  Stomach;  and  immedi- 
ately below  the  A.ch  are  the  Convolutions  of  the  Jejunum. 

In  the  Left  Hvpochondriuro,  it  turns  backwards  under  the 
Spleen,  and  defends  in  the  left  Lumbar  Region,  on  the  fore- 
fide  of  the  Kidney,  to  which  alfo  it  is  clofely  connected. 

In  the  Left  II  ac  Region,  it  forms  two  Convolutions,  com- 
pared in  fhape  to  the  Greek  Sigma , and  hence  called  Sigmoid 
Flexure  of  the  Colon,  wh  ch  afterwards  conllitutes  the  Reftum. 

The  Sigmoid  Flexure  varies  confiderably  in  length  in  different 
perfons,  extendng  fiequently  into  the  Hypogallric  Region,  and 
in  feme  inftances,  as  f r as  the  Inteltinum  Caecum. 

The  Colon,  through  its  whole  extent  is  fixed  to  the  Body  by 
means  of  the  Mefocolon. 

The  Reflum  begins  at  tjte  laft  Lumbar  Vertebra,  and  has  its 
name  from  appearing  ftraight  when  viewed  anteriorly. 

Itdcfeends  upon  the  fore-fide  of  the  Os  Sacrum  and  Os  Coc- 
cygis,  and  terminates  ir.  the  Anus,  a little  beyond  the  extremity 
of  the  lalt  named  Bone. 

In  its  courfe,  it  follows  the  direction  of  the  Bones  over  which 
it  paffes,  turning  firft  downwards,  then  a Hide  backwards,  then 
forwards,  and  is  fixed  to  them  by  the  Mefore&um. 

The  Reftum  differs  from  the  other  Inteftines,  in  becoming 
wider  in  its  prog  refs  downwaids,  and  forming  below  a Refer- 
voir  for  the  Faxes. 

At  the  Anus,  it  contrails  into  a narrow  Orifice,  the  fides  of 
which  are  d'l'pofed  in  clofe  longitudinal  folds. 

Upon  the  Outer  Surface  of  the  Great  Inteftines,  but  more 
efpecially  upon  the  Colon,  are  the  Appendicitis  P inguedinojee , fi- 
tuated  at  different  diftanecs  from  each  other, — thin  at  their  roots, 
becoming  thicker  in  their  bodies,  and  projeiling  from  the  Intef- 
tines like  fo  many  pendulous  Papillae. 

They  are  covered  by  the  Peritoneum,  and  are  of  the  fame 
ftruflure  and  ufe  with  the  Omentum. 

Befides  the  Appendiculae,  there  are  on  both  fides  of  the  adhe- 
fions  of  the  Mefocolon,  Adipofe  Strata , which  are  of  the  fame 
nature  with  the  others. 

The  Colon  is  divided,  longitudinally,  into  three  parts,  by  as 
many  Livamentous-hke  Bands , which  run  upon  its  Su  • f 


100 


One  of  them  goes  along  each  fide  of  the  Colon  ; and  that  molt 
expofed  to  view  when  the  Omentum  is  leparated,  is  the  largeft  : 
The  tliiid,  which  is  the  fmalleft,  and  which  was  difcovered  by 
Morgagni,  is  concealed  by  the  attachment  of  the  Melb-colon. 

They  begin  at  the  root  of  the  Appendix  Vermiformis,  and, 
after  running  along  the  Caecum  and  Colon,  unite  into  two,  and 
then  terminate  on  the  Return. 

Mesentery. 

The  Mefentery  is  formed  by  a doubling  of  the  Peritoneum, 
which  is  detached  forwards,  and  includes  the  Inteftines  as  in  a 
Sling. 

It  is  named  from  its  fituation  in  the  middle  of  the  Inteftines, 
and  is  divided  into  two  parts,  one  connecting  the  Small  Intef- 
tines, and  retaining  the  name  of  Mefentery  ; the  other,  the  Great 
Inteftines,  and  termed  Mefocolon. 

The  Mefentery  begins  at  the  laft  turn  of  the  Duodenum,  and 
runs  obliquely  downwards  and  towards  the  right  fide,-  along  the 
Vertebrae  of  the  Loins,  to  the  firft,  fecond,  and  thiid  of  which 
it  is  chiefly  connected. 

Between  the  two  Layers  of  the  Mefentery,  are  inclofed  a con- 
fiderable  quantity  of  Cellular  Subftance  and  Fat,  the  numerous 
Blood-veffels  and  Nerves,  with  the  LaCteals  and  Glands  of  the 
Jejunum  and  Ilium. 

Its  anterior  edge  is  much  more  extenfive  than  the  pofterior,  be- 
ing plaited  and  folded, — the  Plaits  correfponding  with  the  Con- 
volutions of  the  Inteftines  to  which  it  is  fixed. 

The  Mefo-colon  is  the  continuation  of  the  Mefentery,  which, 
after  reaching  the  lower  extremity  of  the  Ilium,  contracts,  and 
obtains  this  name. 

It  follows  the  courfe  of  the  Great  Inteftines,  and  fixes  them 
in  their  place. 

Under  the  Right  Kidney,  it  is  narrow  and  firm,  and  forms 
the  Right  Ligament  of  the  Colon. 

Oppofite  to  that  Kidney,  it  appears  to  be  loft  by  the  immedi- 
ate adhefion  of  the  Colon  to  the  Kidney  and  Duodenum. 

It  then  tui ns  acrofs,  and  forms  a broad  expanfion,  which  in- 
clofes  the  Arch  of  the  Colon  at  its  anterior  edge;  and  behind, 
it  ieparates  and  inclofes  the  anteiior  part  of  the  Duodenum,  and 
is  fixed  to  the  Spine. 

It  adheres  a little  to  the  under  part  of  the  left  extremity  of 
the  Stom3ch,  and  aftei  wards  defeends  over  the  left  Kidney,  at 
the  under  end  of  which  it  forms  the  left  Ligament  of  the  Colon. 

It  afterwards  expands,  adheres  to  the  large  Pl'oas  Mufcie,  and 
forms  a loofe  fold,  which  retains  the  Sigmoid  Flexure  of  the 
Colon. 

At  the  laft  Vertebra  of  the  Loins,  it  forms  the  Mefore&um, 
which  by  decrees  becomes  narrower,  and  difappears  towards  the 


101 


under  part  of  the  Pelvis,  the  Reftum  being  then  immediately 
connected  to  the  Os  Sacrum. 

Between  the  Layers  of  the  Mefocolon  are  placed  the  Arteries, 
Veins,  and  Nerves,  will*  the  Abforbents  and  Glands  of  the  Co- 
lon. . _ 

The  ufe  of  the  Mefentery,  in  general,  is  to  fufpetid,  connect,  • 
and  retain  the  Inteftines  in  their  places,— to  furnilh  them  with 
an  external  Coat, — to  receive  the^r  Glands,  Veflels,  and  Nerves, 
and  to  allow  the  two  lalt  to  be  properly  diftributed. 

Omentum. 

The  Omentum  or  Canjul,  formerly  called  Epiploon,  from  its 
feeming  to  float  upon  the  Inteftines,  is  a fine  Membranous  Bag, 
intermixed  with  much  Fat,  and  covering  a large  portion  of  the 
Anterior  Surface  of  the  Abdominal  Vifcera. 

It  is  divided  into  Omentum  Gafro-colicum,  and  Omentum  Coli- 
cum,  the  former  common  to  the  Stomach  and  Colon,  the  latter 
proper  to  the  Colon  : They  are,  however,  a continuation  of  one_ 
and  the  fame  lubftance. 

The  Omentum  Gafro-colicum  confifts  of  an  anterior  and  pofte*. 
rior  part,  each  of  which  is  formed  of  two  Membranes  intimate- 
ly unired. 

In  young  fubjefts,  the  Omentum  forms  a diftinft  Bag,  but  in 
old  people,  the  layers  of  which  it  is  compol'ed  become  more  or 
lefs  incorporated,  and  Cribriform  or  Reticular. 

The  Anterior  Layer  is  a continuation  of  the  Peritoneal  Coats, 
produced  from  the  upper  and  under  Surfaces  ef  the  Stomach. 

This  Produ£lion  arifes  from  the  whole  length  of  the  large 
Arch  of  the  Stomach,  and  beginning  of  the  Duodenum  ; — its 
origin  extending  as  far  as  the  Spleen,  and  del’cending  to  a little 
below  rhe  Umbilicus,  efpecially  in  fat  people,— but  without  ad- 
hering to  the  Abdominal  Mul'cles  behind  which  it  is  fituated. 

Its  under  edge  is  refiefled,  to  form  the  Pofterior  Layer,  which 
alcends  without  adhering  ro  the  Small  Inteftines  over  which  it  is 
fpread,  till  it  reaches  the  Arch  of  the  Colon,  to  the  greater  part 
of  which  Arch,  and  to  the  Veflels  of  the  Spleen,  it  is  connected. 

The  Omentum  Colicum  arifes  from  the  right  part  of  the  Arch 
of  the  Colon,  in  the  manner  the  other  part  of  the  Omentum  a- 
riles  from  the  Stomach,  and  fends  downwards  and  to  the  right 
fide  a Cuneiform  Procefs,  10  be  con.ne&ed  to  the  Caecum. 

Befides  the  Omentum,  there  is  a Membrane  much  fmallerthan 
the  former,  fituated  between  the  Liver  and  Stom  tch,  termed 
Omentum  Hepato-gafricum,  or  Omentum  minus  of  Winslow, 
or  Membrana  Macitentior  of  Haller  from  its  having  little  Fat 
in  it. 

It  paffts  from  the  foie-part  of  the  Sinus  of  the  Porta,  to  the 
under  and  back-part  of  the  Liver,  to  be  conne&ed  to  the  whole 

VOL.  II,  I 2 


102 


edge  of  the  (mall  Curvature  of  the  Stomach,  and  to  the  begin- 
ning of  the  Duodenum. 

L ke  the  other  Omentum,  it  is  compofed  of  two  Layers,  but  is 
thinner,  lets  F.-.t,  and  more  uniform  in  its  ftruflure,  and  alfo 
differs  from  it  in  having  no  refleflion  upwards. 

After  the  Omentum  M nus  reaches  the  Stomach,  its  two 
Layers  feparate  from  each  other,  inclofe  that  Vilcus,  and  form 
it;  External  Co  t. 

A.  the  great  Curvature  of  the  Stomach,  they  rejoin,  and  form 
the  Anterior,  then  the  refle&ed  or  pofterior  part  of  the  Omentum 
Mnjus. 

The  pofterior  part 'Separates  again  into  two  Layers,  which 
inclofe  the  Colon,  and  form  its  External  Coat. 

At  the  oppofite  fide  of  the  Colon,  the  Layers  re-unite,  and 
form  the  Mefo  colon. 

By  the  Membrane  thus  continued,  a large  irregular  Bag  is 
foimed,  of  which  the  Omentum  Minus,  Stomach,  and  anteriot 
pori ion  of  the  Omentum  Majus,  conftitute  the  anterior,  and  the 
reflexion  of  the  Large  Omentum,  the  Colon,  and  Mefo-cclon, 
the  pofterior  part. 

At  the  upper  and  right  fide  of  the  Sac,  there  is  a PafTage  large 
enough  to  admit  a Finger,  termed  Foramen  Winslowi. 

It  is  fituated  immediately  behind  the  Coid  of  the  great  Veflels 
which  lead  to  the  Liver,  and  is  of  a Semicircular  form. 

It  is  compofed  of  the  Peritoneum,  under  the  appearance  of  two 
Ligaments  which  connect  the  funounding  parts  to  each  other. 

The  Foramen  of  Winslow  maintains  a communication  be- 
tween the  Large  Sac  of  the  Omentum  and  common  Cavity  of  the 
Abdomen,  from  which  circuniftance,  Fluids  generated  by  dif- 
cnfe  may  readily  pafs  from  one  of  thtfie  Cavities  to  the  other. 

The  Omentum,  by  its  Fatty  nature,  ferves  to  lubricate  the  Vif- 
ccra,  and  prevent  them  from  being  injured  by  friction. 

Structure  of  the  Small  Intestines  in  General. 

The  Structure  of  the  Small  Inteft  nes  is  nearly  fimilar  to  that 
of  the  Stomach,  and  the  number  of  their  Coats  the  fame. 

The  External  Coat,  excepting  in  a port;on  of  the  Duodenum, 
is  a continuation  of  that  part  ot  the  Peritoneum  which  forms  the 
Mefentery.  It  clofely  furrounds  the  lnteftines,  adhering  to  them 
by  fine  Cellular  Subttance. 

The  Second,  or  Mufcular  Coat,  as  in  the  Stomach,  is  compo- 
fed of  two  Planes  ot  Fibres,  the  External  or  Longitudinal  of 
which  are  more  minute  than  the  Internal. 

The  Circular  Fibres  are  diftinft  and  numerous:  They  confift 
of  Segments  of  Circles,  which  unite  at  different  diftances,  fo  as 
to  fui round  ths  Canal. 

The  Longitudinal  Fibres  ffiorten,  and  the  Circular  contract  the 
lnteftines;  and  upon  the  alternate  relaxation  and  contrafticn  of 


103 


thefe  Fibres,  depends  that  Vermicular  motion,  called  Perijialtic, 
by  which  the  Contents  are  pufhed  through  the  Canal. 

The  Third  commonly  called  Nervous  Coat,  like  that  in  the 
Stomich,  is  while  and  firm  and  compoled  of  Cellular  Subftance, 
without  Fat  ; — its  firmnel’s  giving; iirerigth  to  the  Inteftines. 

The  Fourth,  or  Villous  Coat,  differs  from  that  of  the  Stomach, 
in  forming,  with  the  Cellular  Coat,  numerous  tranfverfe  Folds, 
termed  Vatvules  Conniventes , from  their  ferving,  as  a kind  of 
Valves,  to  retard  the  motion  of  the  Food. 

One  edge  of  thefe  Valves  is  fixed  to  the  Inteftine,  the  other  is 
loole.—-  1 hey  are  much  deeper  than  the  Rugae  of  the  Stomach, 
and  placed  oppofite  to  the  Inierftices  of  each  other,  and  are  of 
different  lengths,  not  forming  entire  Circles. 

The  Villi  of  the  Inner  Coat  are  much  more  confpicuous  than 
in  the  Stomach,  being  compofed  not  only  of  the  extremities  of 
Arteries,  Veins,  and  Nerves,  but  particularly  of  the  Mouths  of 
Laffeal  Veffels,  the  Origins  of  which  are  extremely  fmall,  and 
have  a fungous  appearance. 

Numerous  Dufts  of  Simple  and  Compound  Glands  terminate  on 
this  Coat,  for  the  fecretion  of  Mucus. 

The  former  are  called  Solitary,  and  the  latter  Congregate 
and,  form  their  defcribers,  Glandules  Peyeri,  and  Glandules 
Brunneri. 

They  are  in  the  form  of  Papillae,  but  fo  minute  as  feldom 
to  be  leen,  excepting  in  the  difeafed  Hate, — though  they  are  fup- 
pofed  to  be  difperfed  over  the  whole  of  the  Canal. 

Structure  of  the  Small  Intestines  in  Particular. 

The  Duodenum  is  the  laxeft  and  ftraighteft  of  the  Small  Intef- 
tines, and  fo  large  as  to  have  been  conlidered  as  a Ventriculus 
Succenturiatus,  or  Secondary  Stomach. 

It  is  of  a redder  colour  than  the  reft,  has  a thicker  Mufcular 
Coat,  receives  only  a partial  covering  from  the  Peritoneum,  and 
is  fixed  more  clofely  to  the  Body,  without  floating  like  the  other 
Inteftines. 

It  is  perforated  at  the  diftance  of  three  or  four  fingers-breadth 
from  the  Pylorus,  bv  the  ends  of  ihe  B. diary  and  Pancreatic 
Duffs,  for  the  reception  of  Bile  and  Pancreatic  Juice. 

In  the  Duodenum,  the  Laffeal  Veffels  begin  to  make  their  ap- 
pearance, and  numerous  Mucous  Glands  are  found  in  it  efpeci- 
ally  near  the  Pylorus 

The  ufe  of  the  Duodenum  is  to  receive  the  Food  from  the  Sto- 
mach, and  detain  it  till  mixed  with  the  Bile  and  Pancreatic 
Duff. 

The  Jejunurn  differs  from  the  Duodenum  in  deriving  its  com- 
mon Coat  wholly  from  the  Peritoneum,  in  being  Invidtr, — in 
having  a weaker  Muf’euia  Cv  at,  the  external  Fibres  of  which 
are  extremely  minu.e,— in  the  Valval*  Cormiventes  being  larger 


104 


and  more  numerous,— -and  in  the  Villi  and  Lafleals  which  pro- 
ceed from  them  being  much  more  confpicuous. 

The  Ilium  differs  from  the  former  in  being  lefs  in  diameter, 
and  its  Coats  thinnei  and  of  a paler  colour,  and  in  having  fewer 
and  fmaller  La&eal  Veffels.— In  this  Inteftine  theValvulae  Con- 
niventes  gradually  decreafe  infize  and  number,  and  at  length  en- 
tirely  difappea. At  its  under  end,  the  Mucous  Glands  are 
diftin£t  and  numerous. 

The  ufe  of  the  Small  Inteftines  in  general  is, — to  promote  the 
formation  of  the  Chyle, — to  allow  it  to  be  abforbed,  and — to 
propel  the  remains  of  the  food  into  the  Large  Inteftines. 

Structure  of  the  Great  Intestines  in  General. 

The  Great  have  the  fame  number  of  Coats  with  the  Small  In- 
teftines, but  differ  from  them  in  being  thicker  and  (Longer. — The 
Valvulae  Conniventes  are  deep,  and  placed  oppofite  to  each  other, 
and,  as  in  the  Small  Inteftines,  dimimlh  n number  and  in  fize 
towards  the  under  extiem  ty. — The  Villous  appearance  is  much 
lefs  diftin£L — rThe  Mucous  Glands  are  larger,  but  fimpler  than 
thole  of  the  Small  Inteftines, 

Structure  of  the  Great  Intestines  in 
Particular. 

The  Ir.tejlinam  Caecum  is  of  the  fame  general  ftt'ufture  with  the 
reft  of  the  Great  Inteftines.  Its  Villi  are  very  (hort  ; and  it  has 
a number  of  i'olitary  Mucous  Glands,  broader  than  thole  oi  the 
Small  Inteftines,  which,  when  difeafed,  lometimes  appear  like 
fniall-paxy  with  a perforation  in  ea.li. 

The  Appendix  Vermijormu  is  of  the  fame  ftruflure  wi  h the 
other  Inteftines,  contains  no  f aeces,  but  is  furnilhed  with  nume- 
rous Glands  fimiiar  to  thofe  of  the  Duodenum,  the  conents  of 
which  pafs  into  the  Caecum,  a 1 tile  feiow  the  Valve  of  the  Co- 
lon, and  aftift  in  lubricating  that  Inteftine,  and  in  facilitating 
the  expulfion  of  the  Faeculent  M iter. 

In  the  Caecum,  and  beginnm  of  the  Colon,  the  Food  coming 
from  the  Ilium  is  letained  for  fame  time,  and,  in  cor.lcquence  of 
abforjv  ion,  acquires  a grea  er  degree  of  conliftency,  end  lece.ves  a 
foe  id  fmell.  •' 

The  Culvula  Coli , fomtlimes  called  V l-uula  llei,  or  Valvula 
Baughini,  from  its  fuppofccl  dife  verei , ami  Faivula-Tvi.PlX 
from  the  Author  who  gives  a particular  dvfc i iptiou  of  it,  is  iitu- 
ated  at  the  beginning  of  ihe  Colon,  and  is  placed  traniveriely  in 
the  polterior  and  left  part  of  that  Inieftine. 

It  is  formed  of  a pmjeflion  of  the  Villous  and  Nervous  Coats, 
and  Circular  Muicui  n Fibres  of  the  Ilium,  Caecum,  ar.d  Colon, 
and  has  two  Fouls  or  Lip  , with  an  aperture  in  feum  of  a Mouth 
or  Chink  be1  ween  them. 

At  the  ends  of  the  Valves  aie  two  cords,  termed  Retinacula , or 


105 


Freena  Morgagnii,  which  retain  the  Valve  in  its  proper  fitu- 
ation. 

The  Valve  of  the  Colon  allows  a free  paffage  for  the  Contents 
of  the  Small  into  the  Large  Inteftines,  but  completely  prevents 
their  return. 

The  Colon  is  of  a funilar  ftrufhire  with  the  Caecum.— T'ne 
Longitudinal  Mufcular  Fibres  are  collated  upon  it  into  three 
Fafciculi  or  Bands,  which  arife  at  the  root  of  the  Vermiform 
Procefs,  and  are  continued  along  the  Colon  to  the  Reflum. 

The  Longitudinal  Bands  are  (hotter  than  the  inner  parts  of  the 
Colon,  and  of  confequence  afiift  in  contracting  it,  and  forming 
it  into  Plicae,  which  lie  acrofs  the  Gut,  aufwenng  to  the  Valvulx 
Conniventes  ; only  they  are  at  a greater  diftance  from  each  other, 
and  much  larger,  dividing  the  Colon  into  little  apartments,  called 
Cells. 

The  Cells  of  the  Colon , with  their  Partitions,  have  a threefold 
order,  the  Inteftine  being  aimoft  quite  fmooth  or  plain,  oppofite 
to  the  Longitudinal  Bands. 

The  Cells  aflilt  in  preventing  the  too  quick  defcent  of  the  Fae- 
ces. 

The  ufe  of  the  Colon  is,— to  receive  the  Excrementitious  parts 
of  the  Aliment,— to  retain  them,— to  change  them  into  Faeces, 
and  then,  by  the  periftaltic  motion  of  the  Inteftines  and  power 
ef  Refpiration,  to  pulh  them,  by  (low  degrees,  to  the  Re£h>m. 

The  ReSum  differs  from  the  Colon  in  being  covered  only  an- 
teriorly and  laterally  by  the  Peiitoneum  Its  Mufcular  Fibres 
are  ftronger  and  thicker,  and  f read  uniformly  over  the  Inteftine. 
—The  Circular  Fibres  are  fo  thick  at  the  end  of  the  Reclum,  as 
to  have  been  named  Internal  Sphincter. 

It  has  no  Cells  like  the  Colon  ; but  the  Cellular  and  Inner 
Coat  are  fo  much  larger  here  than  they  are  higher  up,  as  to  fall 
into  tranfvetfe  folds,  which,  however,  difappear  in  proportion  to 
the  diftention  of  the  Inteftine. 

The  middle  and  under  end  of  the  Reftum  has  numerous  large 
Mucous  Glands  or, Follicles. 

The  extremity  of  the  Redum  forms  a firm  Circle,  which  afts 
as  a Vaive,  and  afiifts  the  proper  Sphinfter  in  preventing  the  in- 
voluntary difcharge  of  the  Faeces. 

The  Verge  of  the  Anus  is  lurrour.ded  with  deep  Follicles,  the 
contents  of  which  pi  event  the  tendei  Skin  of  the  Anus  from  be- 
ing excoriated  by  hard  or  act'd  Fx  es. 

The  Anus  is  alfo  lurrounded  with  a _ reat  tfeal  of  Fat,  which 
admits  of  the  dilatation  of  the  Reffurn,  and  facilitates  the  dif- 
char  e of  the  Faeces. 

The  Reftum  receives  the  Faeces  from  the  Colon,  retains  them 
for  a cei  tain  time,  till,  by  their  weight  and  Acrid  nature;  it  is 
flimulated  to  difcharge  them  ; which  it  does  by  the  power  of  its 


106 


Mufcular  Coat,  and  of  the  Levator  Ani,  affifted  by  the  aftion  of 
the  Diaphragmatic  and  Abdominal-Mufcles. 

The  Blood-veJJ'els  of  the  Inteftines  are  large  and  numerous,  and 
are  derived  from  d flferenr  fources. 

The  Duodenum  receives  Branches  from  the  Splenic  and  Hepa- 
tic Arteries. 

The  Jejunum,  Ilium,  and  right  half  of  the  Colon,  are  fup- 
plied  by  the  Superior  Mefenti  ic  Artery  ; and  the  lefi  half  of  the 
Colon  with  the  Re£fum,  by  the  Inferior  Mtfemric  Artery. 

The  Veins  of  all  the  Inteftines  fend  their  Blood  to  the  Vena 
Portae. 

The  Abforbents  of  the  Inteftines  are  large  and  numerous. — 
They  arile  from  the  inner  Surface  of  the  Inteftines,  tun  in  the 
Mefentery  and  Mefo-colon,  parting  through  their  numerous 
Glands.— The  Abforbents  of  the  Small  Inteftines  terminate  in 
the  receptacle  of  the  Chyle  ; thole  of  the  Large  Inteftines,  which 
are  fmaller  than  the  former,  gopaitly  to  theThoiacic  Du£l,  and 
partly  to  the  Lymphatics  of  the  Loins. 

The  Nerves  of  the  Inteftines  are  fmall,  but  numerous,  and 
are  derived  partly  from  the  Eighth  Pair,  but  chiefly  fjom  the 
Great  Sympathetic®. 

The  Veflels  and  Nerves  of  the  Omenta  are  Branches  of  thofe 
•whi,ch  fupply  the  Stomach,  and  have  the  name  of  Gajiro - 
Epiploic. 


LIVER. 

The  Liver  is  a large  folid  Mafs,  of  a dufky  red  colour,  fitu- 
ated  immediately  under  the  Diaphragm,  extending  downwai ds 
to  the  margin  of-  the  Thorax,  but  not  going  beyond  t. 

It  is  placed  partly  in  the  Right  Hypochondrium,  which  it  in  a 
great  meafute  fills,  and  partly  in  the  Epigalhium,  reaching  over 
a little  way  into  the  Left  Hypochondrium. 

It  is  convex  and  very  fmooth  on  the  upper  Surface,  where  it  is 
oppofed  to  the  Diaphragm,  though  a l.ttle  flattened  on  the  up- 
per part  of  its  left  fide,  svhere  it  is  placed  oppofite  to  the  Heart. 

It  is  irregularly  concave  on  the  under  fid'-,  where  it  refts  upon 
the  Stomach  and  Inteftines,  and  is  perforated  by  feveral  large 
Blood-vefFels. 

It  is  thick  on  its  right  and  pofterior  part,  and  becomes  gradu- 
ally thinner  towards  the  left  fide  ; is  ohtufe  or  blunt  on  its  pofterior, 
and  acute  or  Jbarp  on  its  anterior  edge, — and  confiderably  broad- 
er ftotn  one  fide  to  the  other,  than  from  before  backwards. 


107 


It  is  divided  into  Prominences  or  Lobes , two  of  which,  called 
Great  and  Small,  or  Right  and  Left  Lobes,  are  fo  confiderable  as 
to  form  the  Body  and  whole  upper  part  of  ibe  Liver— The 
others  are  1’malJ,  and  are  placed  upon  the  under  fide  of  the  for- 
mer. 

The  Great  Lobe  is  placed  obliquely  in  the  Right  Hypochondriac 
Region,  following  the  Curve  of  the  Diaphragm,  and  relts  upon 
the  Pylorus,  Colon,  and  top  of  the  Right  Kidney. 

The  Small  Lobe,  diftingu  fhed  from  the  Great  one  by  a broad 
Ligament,  is  placed  almolt  horizontally,  chiefly  in  the  Hepeaftic, 
and  reaching  only  a little  way  into  the  Hypochondriac  Region. 

—The  other  Lobes  are, — 

The  Lobules  Spigelii,  which  is  fmall  when  compared  with  the 
two  former  Lobes,  but  is  the  principal  one  below. 

It  is  fituated  near  the  Spine,  upon  the  left  fide  of  the  Great 
Lobe,  and  (is  of  a Pyramidal  form,  projecting  like  a Nippie,  at 
the  fmall  Curvature  of  the  Stomach. 

Th e Lobulus  Caudatus,  which  is  merely  the  root,  or  one  of  the 
angles  of  the  Lobulus  Spigelii,  advancing  towards  the  middle  of 
the  lower  fide  of  the  Great  Lobe. 

The  Lobulus  Anonymus , or  Sluadratus,  which  is  placed  between 
the  palTage  of -the  round  Ligament  and  the  Gall-bladder,  and  is 
lefs  prominent,  but  broader  than  the  former  Lobule. 

From  the  Lobulus  Anonymus,  abridge  called  Pons,  or  IJlh- 
mus  Hepatis,  runs  acroi's  the  PalTage  for  the  Round  Ligament,  to 
be  joined  to  the  Left  Lobe  : — It  is  fometimes  awanting. 

Upon  the  under  fide  of  the  Liver,  there  are  feveral  Fiffures , of 
which  the  following  are  the  principal. 

The  Great  Fijfure,  called  Foffa  Umbilicalis,  between  the  Right 
and  Left  Lobes,  at  tile  under  and  tore  part  of  the  Liver. 

This  is  terminated  by  a Notch  at  the  fore-part  of  the  Liver,— 
of  different  depths  in  different  bodies,— and  behind,  it  is  com- 
monly covered  with  the  Bridge  above  mentioned. 

The  Principal  Fiffure,  termed  Sulcus  Tranffoerfus,  or  Sinus 
Fortarum,  extending  from  right  to  left,  between  the  Great  and 
Small  Lobes,  and  bounded  by  thefe  Lobes  at  its  extremities,  and 
by  the  Lobulus  Anonymus  before,  and  by  the  Lobulus  Spigelii 
behind,  the  two  latter  forming  parts  compared  by  the  An- 
cients to  a Gate,  and  therefore  called  Porta. 

The  Deprejfion  between  the  Great  Lobe  and  Lobulus  Spigelii, 
for  the  palTage  of  the  Inferior  Vena  Cava,  which  has  frequently 
a bridge  over  it,  forming  it  into  a Canal. 

A Small  Depreffion,  called  Foffa  DuN us  Venofi,  between  the 
| Left  Lobe  and  Lobulus  Spigelii,  running  a little  obliquely  from 
I right  to  left  fide,  and  receiving  a Ligament,— which  is  a Branch 
I of  the  Umbilical  Vein  in  theFcetus. 


The  Liver  is  conneEled  to  the  Body  by  different  Procejfes, 
termed  its  Ligaments,  all  of  which,  excepting  one,  are  formed  by 
doublings  of  the  Peritoneum,  viz. 

The  Ligamentum  Latum,  or  Sujpenfirium  Hepatis,  placed  be- 
tween the  Right  and  Left  Lobes  above,  and  extending  below  into 
the  FofTa  Umbilical, is. 

It  is  fixed  obliquely  to  the  Diaphragm  and  tip  of  the  Enfiform 
Cartilage,  and  then  del'cends  in  the  fame  oblique  direElion,  ad- 
hering to  the  inner  part  of  the  Vagina  of  the  Right  ReElus  Abdo- 
minis Mufcle,  as  far  as  the  Umbilicus. 

The  Ligamentum  Rotundum, — which  is  the  Umbilical  Vein  in 
the  Foetus,  placed  in  a doubling  at  the  under  part  of  the  Liga- 
mentum Latum,  and  fixed  to  the  Umbilicus. 

Thefe  two  Ligaments  have  been  fuppofed  to  refemhle  a Falx, 
with  the  edge  turned  uppermoft,  from  which  circumftance  the 
Ligamentum  Latum  is  fometimes  alfo  called  Falciforme. 

The  Ligamentum  Dextrum,  or  Right  Lateral  Ligament,  which 
is  fhort,  and  conneEls  the  back-part  of  the  right  extremity  of  the 
Great  Lobe  to  the  Diaphragm. 

The  Ligamentum  Sinifirum,  or  Left  Lateral  Ligament,  which 
is  longer  than  the  former,  and  conneEls  the  left  extremity  of  the 
Small  Lobe  to  the  Diaphragm. 

The  Ligamentum  Coronarium,  confidered  by  fome  as  merely 
Cellular  Subftance,  and  by  others  as  a refleElion  of  the  Peritone- 
um, or  both. — It  unites  the  root  of  the  Liver  to  the  Tendinous 
Portion  of  the  Diaphragm. 

Befides  the  Ligaments  already  mentioned,  two  others  are  de- 
fcribed  by  Haller  ; one  called  Hepatico-colicum,  which  paffes 
from  the  Gall-bladder  and  contiguous  Sinus  Portarum,  acrofs 
the  Duodenum,  to  the  Colon  ; another  called  Hepatico-renale , 
which  defcends  from  the  root  of  the  Liver  to  the  Kidney.— 
Thefe,  as  well  as  the  other  Ligaments  of  the  Liver  in  gene- 
ral, are  produElions  of  the  Per  itoneum. 

The  Ligaments  of  the  Liver-  preferve  it  in  its  proper  fituation, 
and  of  courfe  prevent  it  from  inditing  too  much  in  any  dirt  Elion. 
The  Stomach  and  Inieftmes  fupport  it  when  the  Body  is  upright 
and  the  Diaphragm,  when  the  Body  s inverted. 

The  Liver  has  a Ample  Coat  adhering  clofely  to  it  which  it  de- 
rives from  the.  Peritoneum,  and  is  every  where  covered  by  this 
Membr  ane,  excepting  behind,  where  it  adheres  to  the*Diaphragm 
by  Cellular  Subifance. 

The  Subftance  of  the  Liver  is  eom  ofed  of  feveral  kinds  of 
Veffels,  the  extreme  Branches  of  which  are  intermixed  in  fuch  a 
manner,  as  to  form  numberlefs  Pulpy  Corpufcles,  named  Acini, 
from  a refemblance  to  finall  Stones  or  Kernels  of  Fruit,  which 
when  minutely  examined,  are  obferved  to  be  compofetl  of  Veflels 
in  the  form  of  radiated  Villi  or  Penicilli. 


10® 


The  Vejfels  of  the  Liver  are,  the  Hepatic  Artery,  Vena  Porta- 
rum,  Vena  llcpatica , Abforbents,  and  Biliary  Duels. — It  has 
iikewife  numerous  Nerves. 

The  trunks  of  the  Hepatic  Artery,  Vena  Portas,  Biliary  Dufls, 
and  Nerves,  with  the  Abforbents  and  Lymphatic  Glands  of  the 
Liver,  form  a large  Cord  at  its  under  part. 

The  Artery  is  fituated  in  the  left  part  of  the  Card,  the  Vein 
in  the  right,  with  the  Trunk  of  the  Biliary  Dufls  before  it 
the  Nerves  and  Lymphatics  furrounding  the  great  Veflels. 

The  Cord  of  Veflels  and  Nerves  is  intermixed  with  moch  Cel- 
lular Subftance  and  covered  externally  by  a reflection  of  the  Pe- 
ritoneum, which  has  obtained  the  name  of  Capfule  of  G lisson. 

The  Brandies  of  Veflels  and  Nerves  accompany  each  other- 
through  the  fubftanceof  tire  Liver,  forming  fmall  Fafciculi,  in 
a manner  fomewhat  fimilar  to  that  by  which  the  Cord  is  formed 
by  their  Trunks. 

In  their  courfe  through  the  Liver,  the  Branches  of  the  different 
Veflels  and  Nerves,  but  particularly  thofe  of  tli£  Vena  Portae,  are 
inclofed  in  a large  portion  of  Cellular  Subftance,  which  is  alio 
frequently  called  Capfule  o/Glisson,  from  that  Author  fuppo- 
fing  it  to  be  a continuation  of  the  Capfule  which  covers  the  Vef- 
fels  before  they  enter  the  Liver. 

The  Hepatic  Artery  is  derived  from  the  Caeltac,  and  is  difpsrfed 
throughout  the  whole  fubftance  of  the  Liver,  and  alfo  upon  the 
Coat  which  covers  it,  and  is  fo  fmall  when  compared  with  the 
bulk  of  the  Liver,  as  to  have  been  generally  l'uppofed  to  be  def- 
ined for  the  nourifhment  merely  of  that  Vifcus  ; but  from  in- 
jed  ons  palling  from  the  Artery  to  the  Biliary  Duffs,  and  from 
other  c a ufe;-,  it  has  been  l'uppofed  by  fotne  Anatom  ills,  that  the 
Hepatic  Artery  is  not  only  intended  to  nourilh  the  Liver,  but  is 
capable  of  fecreting  part  of  the  Bile  ; — and  this  fuppolition  is 
farther  confirmed  from  the  Vena  Porta;  having,  in  a recent  cafe 
been  found  awanting,  while,  at  the  fame  time,  the  Hepatic  Ar- 
tery-vus  larger  than  ufual,  and  the  Veins  which  commonly  form 
the  Vena  Portae,  terminated  in  the  Vena  Cava. 

The  Vena  Porta  is  named  from  its  iittmion  with  l efpeff  to  the 
Porta  of  the  L’ver. 

It  partakes  of  the  nature  of  an  Artery  and  a Vein  Like  the 
former  it^carries  the  Blood  from  the  Trunk  to  the  Branches,  and 
like  the  latter,  it  carries  it  ro  the  Heart; — or  it  is  peculiar  in'  the 
Blood,  m one  part  flowing  from  theBranches  to  the  Trunk  and 
in  another  from  the  Trunk  to  the  Branches. 

It  is  formed  by  the  Veins  of  the  Stomach  and  Inteftines,  joined 
to  thole  of  the  Spleen,  Omentum,  and  Pancreas,  and  ap- 
proaches to  the  nature  of  an  artery  in  the  thicknefs  of  its  Coats 
tnougn  it  has  no  puliation. 

It  p.tffes  to  the  Porta,  where,  from  Its  great  flze,  it  is  named 
iiuus  of  the,Vena  Port®,  and  divides  into  Branches  which  ?c 
Vox.,  n.  K 


1 10 

company  thofe  of  the  Artery  in  their  courfe  through  the  fub  Gance 
of  the  Liver,  terminating  at  lad  in  the  Pulpy  Corpufcles. 

The  Vena  Porta  Li  ves  to  carry  Venous  Blood* to  the  Liver, 
for  the  fecretion  of  the  Bile. 

The  Vena:  Hepatic#  are  numerous.  They  are  reflected  partly 
from  the  extremities  of  the  Artery,  and  partly  from  thofe  of  the 
Vena  Pori®.  1 hey  unite  by  degrees,  and  accompany  the  other 
two  fets  of  Vdfels  ; but  at  the  root  of  the  Liver  they  form  two  or 
three  large  Trunks  which  terminate  in  the  Vena  Cava,  where  it 
h about  to  perforate  the  Diaphragm. — They  likewife  fend  off 
feme  final  1 Branches  which  terminate  in  the  Cava,  where  that 
Vein  lies  behind  the  Liver. 

The  Venae  Hepatic®  receive  the  Blood  from  the  Hepatic  Ar- 
tery and  Vena  Port®,  after  the  Bile  has  been  fecretcd,  and  return 
it  to  the  Vena  Cava,  to  be  conveyed  by  it  to  the  Heart. 

The  lymphatics  of  the  Liver  are  fo  numerous  as  to  cover  al- 
molt  the  whole  of  its  outer  Surface.  They  difcharge  their  con- 
tents, partly  intd'the  beginning  of  the  Thoracic  Duff,  and  partly 
to  a Plexus  fituated  in  the- fore-part  of  the  Thorax. 

The  Nerves  of  the  Liver  are  alfo  numerous.  They  ai  ife  from 
the  Great  Syrr.pathctics  and  Eighth  Pair,  and  accompany  the 
Blood-veffels. 

The  Biliary  Duels  aVife  by  extremely- minute  Branches,  termed 
Fori  Bilarii  or  Tubuli  Biliferi,  chiefly  front  the  extremities  of  the 
Vena  Port®,  in  the  SuDltance  of  the  Corpufcles,  through  the 
whole  of  the  Liver. 

The  Pori  Bilarii  run  in  company  with  the  Branches  of  the  Ar- 
tery and  Veins,  and  unite  into  larger  and  larger  Branches,  which 
afterwards  go  into  two,  and  thd'e  again  into  a fingle  Tiunk  in 
the  Sinus  Portarum,  called  Du'S  us  Hepaticus . 

Tite  DuShis  Hepaticus  ferves  to  carry  "The  Gall  or  Bile,  which 
is  of  a yellow  green  colour,  from  the  Liver, — and  to  convey  it 
by  the  power  ot  the  Heart,  Hepatic  Artery,  and  Vena  Pori®, 
alTifted  by  the  preffure  of  the  furrounding  Mul'cles,  to  the  Duo- 
denum, and  partly  to  the  Veficula  Fellis. 

The  Veficula,  or  Cyjlis  Fellis,  or  Gall-bladder , is  a fmail  ob- 
long, Pyriform  Bag,  confiding  of  a Bottom,  Body,  and  Neck, 
fituated  upon  the  concave  fide  of  the  Great  Lobe  of  the  Liver, 
and  placed  in  a tranfverfe  direction  from  belvnd  forwards. 

It  extends  fiom  the  Sinus  Portarum,  where  the  Neck  is  fitu- 
oted,  to  the  anterior  edge  of  the  Liver,  and  when  full  advances 
beyond  the  edge  of  the  Liver,  fo  as  fometimes  to  have  its  Fun- 
dus oppofed  to  the  fofc  parts  of  the  Abdomen,  under  th?  edge  of 
the  Falfe  Ribs. 

The  bottom  is  a little  lower  than  the  Neck,  when  the  Body 
is  in  the  erect  pollute.  It  inclines  alfo  a little  to  the  right 
tide,  and  refls  upon  the  Colon  at  the  beginning  of  the  Duo- 
denum. 


Ill 


It  is  compofed  of  feveral  Coats,  the  external  of  which  is  nr 
continu  r.To.i  of  the  Membrane  of  the  Liver  : i his  however,  is 
on.  ' ,.  rartiai  Coat  covering  that  part  of  th$  Gall-bladder,  which 
prop. cts  neyohd  the  Surface  of  the  L.ter. — It  iiiv.es  to  give 
it'  . ih  to  the  Gall-bladder,  and  to  fix  it  to  the  Liver. 

o er  the  former  Coat,  a few  pale  featured  Fiores,  running 
i,i  V inous  directions,  are  fometimes  oblerved,  which  have  been 
c.ididered  as  a Ahtfcul'ar  Coat  ; and  under  this  is  a fin  all  quanti- 
le of  Cellular  Subltance,  which  has  obtained  the  name  of  Ner- 
vous Coat , 

' lit  Inner  Coat,  fometimes  called  Fillous.,  is. full  of  finall  Re- 
ticular Rugae  or  Folds,  which  become  extremely  minute  towards 
the  CervcX,  where  they  run  in  a longitudinal  direction. 

The  Surface  of  th  s Coat  is  every  where  perforated  by  the 
Ducts  of  final  1 Follicles,  which  diicharge  a vilcid  Mucus,  to  de- 
fend the  Suifaceof  the  Inner  Coat  from  the  Stimulant  natuie  of 
the  Bile. 

The  Gall- Bladder  is  connected  through  its  whole  length  to 
the  Liver  by  Cellular  Sublfance,  Blood- velfels,  and  Abforbenis, 
among  which  the  Hepato-cyJHc  Dull,  limilar  to  thole  round  in 
many  Animals,  were  in  former  times  delcribed,  and  iuppofed 
to  carry  the  Bile  found  in  the  Gall-bladder  immediately  from  the 
Liver.  It  is  now  fufficiently  afeevtained, — that  no  iuc’n  Dufts 
txilf  in  the  Human  Body. 

The  Gall-Bladder  has  Blood -refill?,  abforbents,  and  Nerves, 
in  common  with  thole  of  the  Liver.— Its  Veins  pafs  into  the  Vena 
Portae. 

The  Neck  of  the  Gall-bladder  is  twifted  and  folded  againft  it- 
fe If,  and  afterwards  con: rafts  and  lends  out  a Duct  called  CyJiicuj, 
which  runs  near  the  Dtifius  Hepaticus , and  then  joins  it,  to  form 
the  Duffles  Communis  Ctoledochus . 

The  Duffus  Cijiicus  is  fmalier  than. the  Dtiffus  Hepaticus,  and 
differs  from  it  allbin  having  a number  ef  imperteft  Partitions  or 
Plica',  running  in  a femewhat  fpiral  direction,  and  forming  it  in- 
to Cells  which  retard  the  flow  of  the  Bile. 

The  Gall-bladder  ferves  as  a receptacle  for  the  Bile,  when  the 
Stomach  and  Inteffines  are  empty  and  have  no  need  of  it,  and  re- 
tains it  till  wanted  for  the  purpofe  of  digellion. — It  is  afterwards 
difeharged  from  the  Gall-bladder,  when  the  Stomach  is  full,  in- 
to the  Duftus  Communis,  and  from  that  to  the  Duodenum, 
chiefly  by  the  preflfure  of  the  furrounding  Vifceva,  and  partly  as 
fame  Anatomilis  fuppofe,  by  a contraftile  power  in  the  Gall-blad- 
der iifelf. 

The  whole  of  the  Bile  contained  in  the  Gall-bladder  is  found, 
by  experiment,  to  pafs  from  the  Liver  through  the  Hepatic  Duft 
to  the  Duftus  Communis,  and  from  that  by  the  Cyclic  Duft  into 
the  Gall-bladder.  , 

The  Bile  returning  from  the  Gall-bladder  is  cbferved,  from 
the  thinner  parts  being  abforbtd,  to  be  thicker,,  mere  aciid  and 


Liver. 

The  DuSus  Communis  C.boledochus,  called  Choledochiis,S rum  its 
conveying  Biie,  is  about  the  iize  of  a Goofe-quii],  an .d  is  con- 
siderably larger  than  either  of  theDufts  which  open  into  it. 

It  dei'cends  at  the  pofterior  and  left  part  of  the  Duodenum,  and 
pafl’es  for  1'orcie  way  obliquely  between  the  Mulcular  and  Inner 
Coats  of  that  Gut, — the  obliquity  anfvvering  the  purpofe  of  a 
Valve. 

It  terminates  in  the  left,  pofterior,  and  near  to  the  under  part 
cf  the  I’econd  Turn  of  the  Inteftine,  by  a projecting  Orifice, 
which  is  rounded  above,  and  pointed  below. 

The  Stt  ufture  of  the  Duilus  Chcledochus,  and  of  the  Biliary 
Du£ls  in  general,  is  of  the  fame  nature  being  entirely  Membra- 
nous : The  Inner  Surface  of  the  Dufts  alfo  agree  in  being  per- 
forated by  numberlel's  pores,  winch  are  the  Mouths  of  Mucous 
Follicles,  fimilar  to  thole  upon  the  infide  cf  the  Gall-Bladder. 

The  Bile  ferves  to  mix  t he  different  parts  of  the  Food  properly 
together,  for  the  foimation  of  the  Chyle, — to  correct  too  great 
a difpofition  to  acidity, — and  to  excite  the  Perilfalic  motion  of  tlie 
Inttlfir.es, 

SPLEEN. 

The  Spleen  is  a foft  and  very  Vafcular  Subfiance,  and  of  a 
purple  colour. 

It  is  fomewhat  deprtlTed,  is  of  a long  oval  form,  and  of  a con- 
fiderable  fize,  but  varying  in  this  refpefl  in  different  fubje&s. 

It  is  (ituated  in  the  Left  Hypochondriac  Region,  between  the 
laige  extremity  of  the  Stomach  and  correfponding  Falfe  Ribs; — 
It  sounder  end  lying  behind  the  Colon,  and  over  the  top  of  the 
Left  Kidney. 

The  fu nation  of  the  Spleen  varies  a little,  according  to  the 
(late  of  Refpir-tion,  and  to  the  fullnefs  or  emptinefs  of  the  Sto- 
mach ; — riling  or  failing  as  the  Lungs  ate  lels  or  more  dilated, 
and  becoming  more  oblique  in  its  iituation,— with  its  inferior  ex- 
tremity turned  more  forwards, — in  proportion  as  the  Stomacn 
becomes  more  diftended. 

Its  External  Surface  is  convex  and  uniform,  like  that  of  the 
Ribs,  &c.  to  which  it  is  oppofed. 

Its  Internal  Surface,  or  that  next  the  Spine,  is  irregularly 
concave;  and  is  divided  into  an  Anterior  and  Pofterior  Plane,  by 
a longitudinal  Groove  or  Fifl'ure,  where  the  Veffels  and  Nerves 

enter.  . 

The  Anterior  Plane  is  more  concave  than  the  Pofterior,  ccr- 
refponding  to  the  contiguous  convexity  of  the  Stomach. 

The  SpTeen  has  frequently  deep  Fiffures  upon  its  edges ;— fume- 
times  it  has  ltnall  /Ippendages  attached  to  it,  and  not  unfieouent- 
ly  there  is  one  or  more  Small  Spleens  connetfed  with  it. 


113 

At  the  under  fide,  it  is  fixed  to  the  Omentum,  and,  by  means 
of  that  and  Blood- veffels,  to  the  Stomach  and  Pancreas.— -Be- 
hind, it  is  connedted  to  the  Diaphragm  ; and  below,  to  the  Lett 
Kidney  and  Colon,  by  refledlions  of  the  Peritoneum,  and  by 
Cellular  Subftance. 

It  is  covered  by  a double  Membrane,  one  Layer  of  which  is  a 
production  of  the  Peritoneum,  the  other  proper  to  the  Spleen  it- 
felf  j but  fo  clofely  connedled  to  the  common  Coat,  that  they  ap- 
pear to  be  one  and  the  fame  Membrane. 

The  fubftance  of  the  Spleen  is  remarkably  foft,  and  is  by 
much  the  mod  tender  of  the  Abdominal  Vifcera. 

It  confifts  of  a Congeries  of  Blood-vefl'els,  Lymphatics,  and 
Nerves,  joined  together  and  fupported  by  a large  quantity  of  Cel- 
lular Subftance. 

The  extreme  Branches  of  the  Blood-vefi'els  put  on  the  appear- 
ance of  Penicilli,  or  fmall  Brujhes,  which  have  been  miftaken 
for  Glands. 

Thefe  VelTels  are  fo  tender,  that  when  an  injection  is  forcibly 
thrown  into  either  Artery  or  Vein,  it  burlts  into  the  common 
Cellular  Subftance,  and  gives  the  appearance  of  Follicles  or 
Cells. 

The  Blood-veJJ'els  of  the  Spleen  are  among  the  largeft  of  the 
Body,  in  proportion  to  the  Vilcus  on  which  they  are  dil’perfed. 

The  Artery  is  a principal  Branch  of  the  Caeliac. — It  runs  in  a 
ferpentine  direction,  and,  after  fending  Branches  to  the  Pancre- 
as, &c.  and  the  Arteria  Breves  to  the  left  end  of  the  Stomach, 
it  goes  into  the  fubftance  of  the  Spleen,  where  it  is  fubdivided  in- 
to Branches,  which  are  crowded  together,  and  run  in  every  direc- 
tion, forming  at  length  Plexus  and  Penicilli,  which  terminate  in 
the  Branches  of  the  correfponding  Vein. 

The  Vein,  like  that  in  molt  other  Vifcera,  is  larger  than  the 
Artery: — It  receives  the  Blood  immediately  from  the  termi- 
nations of  the  Artery,  without  the  intervention  of  Ceils. 

The  Splenic  Vein  receives  the  Vena  Breves  of  the  Stomach,  the 
Pancreatic  Veins,  & c.  and  forms  one  of  the  principal  Branches 
ot  the  Vena  Porlx. 

The  Lymphatics  from  the  fuperficial  parts  of  the  Spleen  join 
the  deep  Laied  Abforbents  at  the  Filin  re  where  the  Biood-veffels 
enter,  and  afterwards  pits  through  feveral  Conglobate  Glands 
lying  over  the  Splenic  Artery. 

They  intermix  with  Lymphatics  belonging  to  feveral  other 
Vilcera,  and  terminate  in  the  Thoracic  Duff. 

The  Nerves  of  the  Spleen,  which  are  i’m.ill,  but  confiderable 
in  number,  are  Branches  of  the  Great  Sympathetic  and  Eighth 
Pair,  and  form  an  irregular  Plexus  which  furrounds  the  Veflels. 

No  Excretory  Duff  has  been  found  to  proceed  from  the  Spleen, 
in  confequenc|  of  which  very  various  opinions  have  been  enter- 
tained with  refpefil  tc  the  nfe  of  that  Organ. 

Yol.  II.  K id 


Many  of  the  ancients  were  of  opinion,— that  befides  the  Bile 
of  the  Liver,  there  was  an  Atra  Bills,  or  Black  Bile,  and  that 
the  Spleen  was  the  re.cepticle  of  the  latter. 

Others  have  thought  a particular  Menflruum  was  fecreted  in  it, 
and  conveyed  to  the  Stomach  for  the  purpofe  of  digeftion. 

Others  again,— that  the  Blood  of  the  Spleen  promotes  the  flug- 
giflr  circulation  of  the  Blood  of  the  Vena  Portae. 

The  late  Mr.  Hewson,  who  has  written  particularly  on  the 
Spleen,  was  of  opinion  it  concurred  with  the  Thymus  and  Lym- 
phatic Glands,  in  forming  the  red  Globules  of  the  Blood,  and 
that  thele  Globules  were  rendered  complete  in  the  Spleen. 

It  h as  been  alfo  fuppofed,— that  as  the  Stomach  becomes  full, 
the  Spleen  is  compreffed  by  it,  in  confequence  of  which  a greater 
quantity  of  Blood  is  fent  to  the  Pancreas,  for  the  Secretion  of 
the  Pancreatic  juice. 

But  the  prefent  moll  prevalent  opinion  is,— that  the  Blood  un- 
dergoes fome  change  in  it,  which  renders  it  ufeful  in  the  fe- 
cretion  of  the  Bile  and  the  opinion  is  fupported  from  the 
great  quantity  of  blood  with  which  this  Organ  is  known  to  be 
fupplied,  and  from  its  Vein,  not  only  in  Man,  bet  in  other  ani- 
mals, palling  to  the  Vena  Portae. 

PANCREAS. 

The  Pancreas,  i.  e.  AllFleJh , or  the  Sweat  Bread,  is  a long 
flat  Gland  of  the  Conglomerate  kind,  and  of  the  fame  nature 
with  the  Salivary  Glands,  of  which  it  may  be  reckoned  the 
largeft. 

It  is  lituated  in  the  Epigaftric  Region,  and  is  placed  tranfverfe- 
ly  in  the  back-part  of  the  Abdomen,  between  the  Stomach  and 
Spine. 

It  has  a large  or  Right  Extremity,  and  a Small  or  Left  one,  an 
Anterior  and  Pofterior  Surfaee,  and  an  Upper  and  Under  Edge. 

The  Right  Extremity  is  attached  to  the  left  fide  of  the  Second 
Turn  of  the  Duodenum,  or  to  that  part  where  the  Inteftine  is 
about  to  go  acrofs  the  Spine. 

From  the  under  part  of  the  Right  Extremity,  the  Pancreas 
fends  down  an  Elongation  or  Procefs,  which  adheres  clofely  to 
the  Duodenum. 

This  Procefs  was  difeovered  by  Winslow,  and  termed  by 
him  Pancreas  Minus. — It  is  alfo  called  Head  of  the  Pancreas. 

The  Body  of  the  Pancreas  palfes  before  the  upper  part  of  the 
tranfverfe  portion  of  the  Duodenum,  and  over  tire  Aorta,  Vena 
Cava,  and  part  of  the  Splenic  Velfels,  to  all  of  which  it  is  at- 
tached. 

The  fmall  extremity,  which  is  rounded,  is  fixed  to  the  Spleen, 
through  the  medium  of  the  large  Omentum. 

The  Pancreas  is  covered  anteriorly  by  the  two  Layers  of  the 
root  of  the  Mefo-colon  5— pofteriorly,  it  is  only  covered  with 
Cellular  Subfiance,  which  conneas  it  to  the  Vertebras 


It  is  composed  of  Acini,  which  form  fmall  Glands  or  Lobes  ; 
and  thefe  are  connefted  loofely  by  Cellular  Subftance,^n  fuch  a 
manner  as  to  give  an  appearance  of  uniformity  and  lihosthnefs 
to  the  External  Surface. 

The  Arteries  of  the  Pancreas  are  derived,  partly  from  the  He- 
patic, but  chiefly  from  the  Splenic,  by  f'everal  fmall  Branches, 
which  pafs  at  various  places  into  its  Subftance,  in  a tranfverfe 
direftion. 

The  Feins  correfpond  in  name  and  courfe  with  the  Arteries, 
and  aflift  in  forming  the  Vena  Portae. 

The  Lymphatics  run  to  the  Splenic  Plexus,  and  terminate  in 
the  Thoracic  Duft. 

The  Nerves  of  the  Pancreas  are  fmall  : Like  thofe  of  the  o- 
ther  Vifcera  of  the  Abdomen,  they  are  derived  from  the  Great 
Sympathetic  and  Eighth  Pair. 

From  the  different  Acini  of  the  Pancreas,  fmall  Duffs  arife, 
which  join  into  larger  ones  running  tranfverfely  in  the  Subftance 
of  the  Pancreas,  and  forming  a common  Duff,  called  Duflus 
Pancreaticus. 

The  Pancreatic  Dud,  termed  alfo  Duiius  Wirtsungi,  after 
the  difcoverer  of  it  in  the  Human  Body,  is  remarkably  thin,  of  a 
white  colour,  and  femi-tranfparent. 

It  begins  at  the  Left  Extremity  of  the  Pancreas,  runs  in  the 
fubftance  of  the  Gland,  a littlh  below  its  middle  height,  and  be- 
comes gradually  larger  in  confequence  of  receiving  tiie  different 
Branches  which  compofe  it,— and  is  at  laft  about  the  fize  of  a 
Raven’s-quill. 

At  the  Right  Extremity  of  the  Pancreas,  it  receives  the  Prin- 
cipal Duft  of  the  Pancreas  Minus,  and  terminates  obliquely  in 
the  Duodenum  along  with  the  Duftus  Communis  Choledochus. 
— In  fome  rare  cafes,  however,  it  terminates  at  a little  diffance 
from  the  Biliary  Duft;  and  fometimes  alfo,  the  Duff  of  the  Pan- 
creas Minus  ends  feparately  in  the  Duodenum. 

The  Pancreas  fecretes  a Liquid  or  'Juice,  refembling  Saliva 'in 
quality  and  appearance,  and  difcharges  it  by  its  Excretory  Duft 
into  the  Duodenum. 

The  Pancreatic  Juice  incorporates  the  Bile  with  the  Alimen- 
tary Mafs,  and  may  be  faid  alfo  to  anfwer  the  fame  purpofe  to  the 
contents  of  the  Inteffines,  which  the  Gaftric  Juice  does  to  ihofe 
of  the  Stomach  ; — or,  it  finifhes  that  digeftive  Procefs  in  the  In 
teftines  which  was  begun  in  the  Stomach. 


116 


OF  THE 

ORGANS  OF  URINE  AND  GENERATION 


IN  THE  MALE. 


KIDNEYS. 


The  Kidneys  are  two  Glandular  bodies,  of  a pale  red  colour, 
fituated  in  the  upper  and  back-part  of  the  Abdomen,  in  the  Lum- 
bar Region. 

They  are  placed  one  on  each  fide  of  the  Spine,  extending  from 
the  Eleventh  Pair  of  Ribs  to  near  the  Ofia  Ilia  ; and  reft  upon 
the  Diaphragm,  large  Pfoae,  Quadrati  Lumborum,  and  Tranf- 
verfales  Abdominis  Mufcles. 

The  Right  Kidney  is  fituated  at  the  under  and  back-part  of 
the  large  Lobe  of  the  Liver,  behind  the  Colon,  and  is  common- 
ly a very  little  lower  than  the  left. 

The  left  Kidney  is  placed  at  the  under  and  back-part  of  the 
Spleen,  and  behind  the  left  parts  of  the  Stomach,  Pancreas,  and 
Colon. 

The  Kidney  is  about  five  or  fix  fingers -breadth  in  length,  but 
confiderably  let's  from  the  outer  to  the  inner  fide,  and  lefs  than 
that  ftii)  from  before  backwards;  or,  it  is  compared  in  ftiape  to 
a French  or  Kidney  bean. 

It  is  rounded  anteriorly,  flattened  pofteriorly,  convex  and  uni- 
form at  its  outer  margin,  and  has  a deep  deprefiion  or  Sinus  to- 
wards the  Vertebrae,  furrounded  with  unequal  edges,  where  the 
Renal  Veflels  and  Nerves  enter. 

It  is  a little  broader  behind  than  before,  and  a little  broader 
and  more  curved  above  than  below,  from  which  circumftanee, 
but  more  particularly  from  the  dilpofition  of  the  Veflels  to  be  af- 
terwards mentioned,  it  is  enfy  to  diftinguifh  the  Right  from  the 
Left  Kidney  when  taken  out  of  the  Body. 

The  Right  Kidney  is  connected  to  the  Liver  and  Duodenum, 
the  Left  to  the  Spleen,  and  both  to  the  Mufcles  on  which  they 
are  placed,  and  to  the  Renal  Glands  and  Colon,  by  Cellular 
Subrtance  and  by  the  Peritoneum. 

They  are  alfo  conne&ed  to  the  Aorta  and  Vena  Cava  by  the 
Blood-vefl'els,  and  to  the  Bladder  of  Urine  by  the  Ureters. — 


117 


They  accompany  the  motions  of  the  Liver  and  Spleen,  in  the  dif- 
ferent Hates  of  Relpiration. 

Each  Kidney  is  furrounded  by  loofe  Cellular  Subftanc#,  which 
commonly  contains  a confidera'ole  quantity  of  Fat,  from  which 
it  is  termed  Tunica  Adipofa . 

The  Tunica  Adipofa  covers  not  only  the  Kidney,  but  large 
Veffds,  and  defends  them  from  the  prelfure  of  the  furrounding 
Vifcera. 

Under  the  Tunica  Adipofa,  there  is  a Membrane  campofed  of 
-the  original  proper  Coat  and  Cellular  Subliance  incorporated, 
which  adheres  clofely  to  the  Kidney,  and  is  rcflefled  over  the 
edges  of  the  Sinus,  toLe  joined  to  the  Pelvis  and  large  Veffels. 

The  fubltance  of  the  Kidney  is  commonly  fmooth  and  uni- 
form, though  fometimes  it  is  irregular,  in  coniequence  of  the 
Lobes  which  originally  form  it  not  being  completely  incorpora- 
ted.— It  conlifls  of  an  outer  part  called  Cortical,  and  an  inner 
termed  Medullary. 

The  Cortical  Subfancc,  termed  alfo  Secerning,  furrounds  the!1 
Kidney,  and  forms  about  a third  ;of  its  breadth  ; — it  likewife 
fends  in  Precedes  or  Partitions,  which  feparate  the  Medullary 
parts  from  each  other. 

The  Medullary,  termed  alfo  Uriniferous  Subfance,  is  of  a red- 
der colour  than  the  former,  and  is  divided  into  a number  of  dif- 
tinft  Columns,  each  of  which  terminates  in  a proje&ion  called 
Papilla,  or  Procejfus  Mammillaris* 

The  PapilLe  are  merely  the  continuation  of  the  Uriniferous 
part ; though  frequently  conlidered  as  a third  division  of  the  fub- 
lfance  of  the  Kidney. 

Each  Kidney  has  one,  and  fometimes  more  Arteries,  which 
run  trar.fverfely  from  the  Aorta,  and  a Vein  ft;  11  larger,  .which 
terminates  in  the  Cava. — They  enterat  the  Sinus  of  the  Kidney, 
and  are  included  in  Cellular  Subliance,  which  accompanies  them 
throughout  their  courfe. 

The  Right  Renal  Artery  is  longer  than  the  Left,  in  confe- 
quence  of  the  Vena  Cava,  behind  which  it  palfes,  being  placed 
upon  the  Right  Side  of  the  Aorta. 

1 he  Artery,  as  it  approaches  the  Kidney,  is  divided  into 
Branches,  which  are  afterwards  minutely  d.ftributed  through 
the  Cortical  Subliance,  forming  Arches  and  Analtomofes  ; — but 
thefe  are  found  to  be  much  Id’s  frequent  than  are  commonly  de- 
feribed. 

7 he  fmall  Branches,  after  turning  and  winding  in  var  ous  di- 
reiSticns,  pafs  partly  towards  the  Surface  of  the  Kidney,  where 
they  form  irregular  Stars,  fonieof  which  fupply  the  proper  Mem- 
brane. 

Others  turn  inwards  in  a waving  direction,  and  form  Corpuf- 
cles,  which  are  difpofed  fomewhat  after  the  manner  of  Clufsrs  of 
fmall  Berries,  which  can  only  be  feen  diltinftly  by  the  aliitlance 
of  Glades,  after  a minute  injefiicn. 


The  Corpufcles  were  eonfidered  by  Dr.  Nichols  as  the  Glo- 
bular .termination  of  Blood-velTels,  and  termed  by  him  Globuli 
Arteriarum  Termini-, — but  thei'e  Globuli  were  afterwards  ob- 
l’erved  by  Mr.  Hewson  to confift  of  final  1 Veffels  intimately  in- 
termixed. 

The  Ve ins  returning  from  the  extremities  of  the  Arteries  unite 
in  the  Cortical  Subftance  of  the  Kidney. 

The  Blanches  of  the  Renal  Vein  are  much  larger  than  thole 
of  the  Artery,  but  correfpoml  with  them  in  their  courle. — They 
form  a large  Trunk  on  each  fide,  which  lies  anterior  to  the  cor- 
refponding  Artery,  and  runs  tr.mfverfely  to  the  Cava  ; — the  left 
which  is  the  larger  of  the  two,  parting  acrofs  the  fore  pai  t of  tl 
Aorta, 

The  Lymphatics  of  the  Kidney  run  from  without  i.nwards,  and 
terminate  in  the  Lumbar  Glands,  and  aftei  wards  in  the  Thora- 
cic Du£t. — The  Superficial  Lymphatics  are  fo  fmall,  as  Ibidem 
to  be  feen,  excepting  in  the  difealeri  it  ate  of  the  Kidney. 

The  Nerves  aie  from  the  Scmilunai  Ganglion  formed  by  the 
great  Sympathetic  and  Nighth  Pair.  They  form  a Plexus  which 
furrounds  the  Blood- vertels,  and, accompanies  them  in  the  Kidney, 

From  the  minute  Extremities  of  the  Renal  Artery,  in  the  Cor- 
puicles  feated  in  the  Cortical  Subftance,  the  Uriniferous  Tubes 
arife.  They  are  mixed  with  fome  extremely  fmall  Blood- veffels. 
and  conftitute  the  Medullary  Subftance  of  the  Kidney. 

By  degrees  they  unite  into  larger  Tubes,  which  run  in  a ra- 
diated  manner,  the  direflion  being  from  the  outer  edge  or  citcum- 
fer?ncej  towards  ih?  inner  part  or  Cavity  of  the  Kidney. 

The  radiated  Tubes,  becoming  ftill  larger  in  their  pafl’age,  ter- 
minate in  the  Papilla ’,  which  are  of  a comprefled  conical  form, 
and  are  at  a little  diftance  from  each  other. 

The  Papilla  are  twelve  or  more  in  each  Kidney,  the  number 
varying  according  to  that  of  the  original  Lobes  of  which  the 
Kidney  is  compoied,  and  likewife  from  fome  of  the  Papillae  be- 
ing incorporated  with  each  other. 

Upon  the  points  of  the  Papilla?  are  the  terminations  of  the  Ui  i- 
niferous  Tubes, — large  enough  to  be  diltinguifhed  by  the  naked 
Eye, — through  which  the  Urine  diftils  from  the  Subftance  of  the 
Kidney. 

Round  the  root  of  each  Papilla,  a Membranous  Tube  arifes, 
termed  Infundibulum  or  Calix,  which  receives  the  Urine  from  the 
Papilla?. 

The  Infundibula  are  commonly  the  fame  in  number  with  the 
Papilla?  ; the  number,  however,  varying  in  different  fubje£ls,  two 
or  more  of  the  Papillae  fometimes  opening  into  the  fame  Infundi- 
bulum. 

The  Infundibula  join  into  two  or  three  larger  Trunks,  which 
afterwards  form  a Dilatation  of  confulerable  llze,  of  the  fttape  of 
an  inverted  Cone,  and  termed  Pelvis  of  the  Kidney. 


119 


The  Pel-vis  is  placed  partly  within,  but  the  greateft  part  of  it 
without  the  body  of  the  Kidney,  and  contrails  into  a long  Tube, 
about  the  fize  of  a Writing-pen,  called  Ureter. 

The  Ureters  are  commonly  one  to  each  Kidney,  though  in 
fomc  rare  inftances  they  are  double  on  one  or  on  both  Tides. 

The  Artery  of  the  Kidney  is  placed  uppermoft, — the  Vein  in 
the  middle  and  fore-part,— and  the  Pelvis  and  beginning  of  the 
Ureters  at  the  under  and  back-part  of  the  Blood-veffels. 

The  Ureters  delcend  obliquely  inwards  behind  the  Perito- 
neum, and  go  over  the  great  Pfoae  Mufcles  and  Iliac  Veffels,  op- 
pofite  to  the  anterior  and  lateral  parts  of  the  Os  Sacrum. 

They  pafs  afterwards  into  the  Pelvis,  and  terminate  in  the  un- 
der, outer,  and  back-part  of  the  Bladder. 

In  their  defeent,  they  are  not  ftraight,  but  form  turns  which 
are  commonly  compared  to  the  Italic neither  are  they  cylin- 
drical, as  they  form  night  dilatations  and  contractions  in  their 
courfe,  two  of  which  contraflions  a;e  more  obfervable  in  their 
paffage  over  the  Pfoae  Mufcles,  and  at  their  infection  into  the 
Bladder. 

The  Ureters  are  covered  anteriorly  by  the  Pertoneum,  and 
compofed  of  an  External  Membranous  Coat , a middle  Mufcuiar 
one,  formed  chiefly  of  circular  Fibres,  and  an  Internal  Coat , 
fometimes  called  Villous. 

The  Inner  Coat  is  very  Vafcular,  and  is  perforated  hy'the 
Mouths  of  fmall  Du6ls,  which  line  it  with  a Mucus  to  defend  it 
from  the  Urine. 

The  Veffels  and  Nerves  of  the.  Ureters  are  from  thofe  of  the 
contiguous  parts. 

The  Ufe  of  the  Kidneys  is  to  fecrete  the  Urine  from  the  Blood, 
and  couvey  it  by  means  of  the  Ureters  tu  the  Bladder. 

RENAL  GLANDS. 

The  Renal  Glands , termed  alfo  Capfula:  Atrabilaritr,  Capfula 
Renales,  Renes  SUccenturiati,  and  Glandulee  Suprarenales,  are  two 
final!,  flat.  Glandular-like  bodies  of  a dark-yellow-colour,  ly- 
ing in  the  upper  and  back-part  of  the  Abdomen. 

They  are  lituated  at  the  upper,  inner,  and  fore-part  of  the 
Kidneys,  over  the  large  Pfoae  Mufcles  and  Diaphragm,  and  high- 
er than  the  Renal  Veffels. 

They  are  of  an  irregular  figure,  and  are  about  a couple  of  fin- 
gers-breadth  in  length,  but  much  larger,  proportionally,  in  the 
Foetus  han  in  the  Adult. 

The  Right  one  is  connected  to  the  Liver,  the  Left  to  the  Spleen 
and  Pancreas,  and  both  to  the  fmall  Mufcle  of  the  Diaphragm, 
and  to  the  Pfose  Mufcles  and  Kidneys,  by  Cellular  Subftanc'e. 
They  are  likewile  retained  by  numerous  Veffels  and  Nerves  which 
aie  fpread  over  them. 


120 


They  are  furrounded  by  Cellular  Subftance,  which  is  part  of 
the  Tunica  Adipofa  of  the  Kidneys,  and  have  a thin  proper  Coat, 
wh’ch  adheres  firmly  to  them. 

They  are  frequently  obferved  to  be  hollow,  and  to  contain  a 
dark-coloured  Bilious-like  matter,  which  is  confidered  by  many 
Anatomifts  as  the  Internal,  very  Vafcular  and  tender  parts  melted 
down  by  putrefaction. 

Their  Arteries  come  from  thofe  of  the  adjacent  parts,  particu- 
larly from  the  Renal,  and  alfo  from  the  Aorta,  and  Diaphrag- 
matic Arteries. 

Of  the  principal  Veins,  the  Right  goes  to  the  Vena  Cava,  and 
the  Left  to  the  Renal  Vein. 

The  Lymphatics  go  chiefly  to  thofe  of  the  Kidneys. 

The  Nerves  come  principally  from  the  Renal  Plexus. 

They  have  no  Ex-  retory  Du£ts. 

The  Renal  Glands  have  been  l'uppofed  to  furnilh  Lymph  for 
the  dilution  of  the  Blood  returning  in  the  Renal  Veins,  after  the 
discretion  of  the  Urine; 

Or, — to  reftore  to  the  Blood  of  the  Vena  Cava  the  irritable  parts 
which  it  lofes  in  the  l'ecretion  of  the  Urine  and  Bile  ; 

Or,-— to  convey  fomething  ufeful  to  the  Thoracic  Duff  ; 

Or,  in  the  Foetus,; — to  divert-the  Blood  from  the  Kidneys,  and 
thereby  leflen  tide  quantity  of  Urine. 

But  their  ufe  is  ltill  undifcovered  ; though  it  is  fuppofed  from 
their  vicinity  to  the  Kidneys,  not  only  in  Man,  but  in  many  o- 
ther  animals,  that  they  are  fubfervient  to  tilde  Organs,  and  par- 
ticularly to  thofe  of  the  Foetus. 

VESICA  URINARIA. 

The  Vefica  Urinaria , or  Bladder  of  Urine,  is  a large  Sac  fitu- 
ated  in  the  Pelvis  of  the  Abdomen,  in  the  bottom  of  the  Hypo- 
gaftric  Region. 

It  is  placed  in  the  fore-part  of  the  Pelvis,  behind  the  Oft'a  Pu- 
bis, and  before  the  upper,  and  above  the  under  portion  of  the  In- 
teftinum  RcClum. 

When  empty,  it  is  contracted  into  a final]  fize,  which  occupies 
the  underand  fore  part  of  the  Pelvis;  but,  when  fully  diltended, 
it  rdes  above  the  brim  of  that  Cavity,  and  fometimes  afcends  to 
within  a little  diftance  of  the  Umbilicus. 

When  moderately  dilated,  it  is  of  a roundifh,  or  irregular  ob- 
long form,  but  a little  flattened  before,  more  convex  behind,  and 
broader  at  its  anterior  and  pofterior,  than  towards  its  lateral 
parts, — a little  more  capacious,  alio,  below  than  above,  efpecially 
at  its  pofterior  part. 

It  is  dillinguilhed  into  Fundus,  Body,  and  Cer-vix,  the  fuft  of 
which  is  placed  upwards  and  a little  forwards  ; — the  l.ifl  at  the  un- 
der and  fore- part. 


121 


It  is  connected  below  to  the  Reflum,  and  at  the  Tides  to  the 
Pelvis  by  the  reflefted  Peritoneum  and  Cellular  Subftance,  the 
former  of  which,  when  the  Bladder  is  empty,  has  the  appearance 
ef  lateral  Ligaments. 

It  is  attached,  at  the  fore-part  of  its  Body,  by  Cellular  Sub- 
ftance, to  the  Ofl'a  Pubis,  without  the  intervention  of  the  Perito- 
neum. 

It  is  alfo  fixed  to  the  Umbilicus  by  three  Ligaments  fituated 
between  the  Peritoneum  and  Abdominal  Ivlufcles. — They  are 
formed  of  the  Urachus  running  upwards  from  the  Fundus,  and 
the  ftu  ivellcd  Umbilical  Arteries  palling  obliquely  from  the  fides 
of  the  Bladder. 

The  firmed  connexion  is  by  means  of  a Ligamentous  expan- 
sion, which  runs  from  each  fide  of  the  Neck  of  the  Bladder  and 
Proftate  Gland,  to  be  fixed  to  the  infide  of  the  Arch  of  the  Ofia 
Pubis. — It  is  connected,  aifo,  at  this  p ace,  to  the  Penisj'  by  the 
Urethra. 

It  is  compoftd  of  different  Coats  joined  together  by  Cellular 
Subftance,  the  firfit  of  which  is  only  a partial  one  dontinued  from 
the  Peritoneum. 

The  Peritoneal  or  Common  Coat,  recedes  from  the  Abdominal 
Mufcles  at  the  top  of  the  Pubes,  and  palfea  over  the  Superior,  and 
clown  upon  the  porterior  and  lateral  parts  cf  the  Bladder,  to  near 
the  termination  of  the  Ureters,  where  it  is  about  a finger’s- length 
from  the  Anus, — and  is  there  reflefted  upon  the  Refturn  and 
back  part  of  the  Pelvis. 

When  the  bladder  is  much  diftended,  it  carries  the  Peritoneum 
with  it,  and  leaves  a fpace  between  that  Membrane  and  the 
Pubes,  of  fuch  length,  that  an  incifion  has  frequently  been  made 
here,  and  large  Calculi  extracted  from  the  Bladder,  'without  pe- 
netrating into  the  Abdomen,  or  wounding  the  Peritoneum. 

The  fecond  Coat  is  termed  Mufcular. — It  is  compofed  of  dif- 
tinci  Fleftry  Fiores,  interwoven  with  each  other,  and  forming 
Fafciculi. 

The  F.xternal  Fibres  run  clmfiy  in  a longitudinal  direflion, 
and  are  connected,  at  the  under  and  fore  part  of  the  Bladder, 
with  the  Ofia  Pubis. 

More  internally,  are  Fibres  which  run  ir.  all  direflions,  arid 
are  intermixed  with  each  other  in  the  form  of  Net-work. 

The  Mufcula^  Fibres  are  contrafted  about  the  Neck  of  the 
Bladder,  and  form  what  has  been  termed  SphinBer  Vejlcee  •_ 
thefe,  however,  are  merely  the  continuation  of  the  other  Fibres. 

The  Mufcular  Coat,  by  its  contra&ioB,  occafions  the  complete 
evacuation  of  the  Bladder. — The  Fibres  about  the  Neck  of  the 
Bladder,  by  ailing  leparately  from  the  reft  of  the  Mufcular  Coat, 
prevent  the  involuntary  difeharge  of  the  Urine. 

The  Cellular  Subftance,  under  the  Mufcular  Fibres,  is  fre- 
quently termed  Nervous  Coat. 

Vol.  II.  L 


122 


The  Intier  Coat,  though  often  called  Villous,  is  fmooth  like  the 
iniide  of  the  Peritoneum,  and,  though  thin,  is  fo  denfe  as  to  pre- 
vent the  exfud.ition  of  the  Urine. 

This  Coat  is  rendered  fomewhat  unequal  by  the  projefling  of 
the  Falciculi  of  the  Mufcular  Fibres  ; and  when  the  Bladder  is 
empty,  it  forms  large  wrinkles  or  Rugae. 

The  infide  of  the  Bladder  is  very  irritable,  in  eonfequence  of 
•which  a delire  to  expel  the  Urine  is  occasionally  excited.  It  is 
lined,  however,  by  a Mucus,  difcharged  from  its  Arteries,  which 
prevents  it  from  being  conftantljr  ii  ritated  by  that  Fluid. 

The  under  part  of  the  Bladder  is  perforated  by  three  Openings, 
of  which  one  is  placed  anteriorly,  and  two  pofteriorly. 

The  Anterior  Opening  is  the  beginning  of  the  Pnlfage  called 
Urethra,  and  is  furrounded  by  the  Neck  of  the  Bladder. 

It  comes  off  aimoft  at  a right  angle  from  the  lower  part  of  the 
Bladder,  wi tliout  any  tapering  of  that,  Vifcus. 

The  other  two  openings  are  formed  by  the  termination  of  the 
Ureters,  which  run  obliquely  forwards  and  inwards,  between 
the  Mufcular  and  Inner  Coat  of  the  Bladder. 

They  terminate  in  the  Bladder  at  a little  diftance  from  each 
other,  and  at  the  fame  ddtance  behind  the  beginning  of  the  Ure- 
thra, each  by  a fomewhat  oval  Opening,  which  is  more  contract- 
ed than  the  Ureter  is  immediately  above  it. 

The  Arteries  of  the  Bladder  corne  from  various  fources,  but 
chiefly  from  the  Umbilical  and  Pudenda  Communis. 

The  Veins  return  to  the  Internal  Iliacs  : — They  form  a Plex- 
us of  confiderabie  fize  upon  each  fide  of  the  Bladder. 

The  Lyhiphatics  accompany  the  principal  Veins  on  the  Blad- 
der, and,  at  the  under  part  and  fides,  pafs  into  the  Iliac  Glands. 

' Xhe  Nerves  are  Branches  of  the  Great  Sympathetic  and  Sa- 
cral Nerves. 

The  Bladder  receives  the  Urine  from  the  Ureters  by  drops, and 
fometimes  by  fmall  thread-like  ftreams  or  fquirts,  till  by  its  ac- 
cumulated quantity  and  aciimony,  it  forces  that  Vifcus  to  con- 
tract and  expel  it. 

The  Urine  is  expelled,  partly  by  the  contraflion  of  the  Blad- 
der itfel  f,  and  partly  bv  the  a£lion  of  the  Abdominal  Mufcles  and 
.Piaphrs  gm.prtfilng  the  Intclfines  again  if  the  Bladder. 

The  frequency  of  the  evacuation  depends  upon  the  fize  and 
fenfib.lity  of  the  Bladder,  upon  the  quantity  of  Urine  fecreted, 
and  the  degree  cf  acrimony  it  pofleffes. 

TESTES. 

The  Tejlcs,  formerly  termed  Didymi  or  Gemini,  are  two  Glan- 
dular Bodies  floated  in  the  Cavity  of  the  Scrotum. 

The  Scrotum,  which  furniftVes  an  external  covering  to  the 
Te!?f s,'is  a continuation  of  the  common  Integuments,. .has  the 


123 


fame  Stru'Sure  with  the  Skin  in  general,  but  is  more  plentifully 
l'un plied  with  Sebaceous  Follicles,  has  no  fat  in  its  Cellular  Sub- 
fta'nce,  and  is  occafionall;  relaxed  and  corrugated  in  a greater  de- 
gree than  the  Skin  in  the  other  parts  of  the  Body. 

Upon  the  Suiface  of  the  Scrotum,  there  is  a luperftcial,  longi- 
tudinal projecting  Line,  which  divides  it  into  two  equal  parts, 
and  has  the  name  of-  Raphe. 

The  in;  er  Surface  of  the  Scrotum  is  lined  with  Cellular  Sub- 
ftance,  winch  is  firmer  and  more  Vafcular  than  in  other  places. 

The  Cellul  r Subihuice  of  the  Scrotum,  in  ccnfequenc'e  of 
its  rednefs.  Fibrous  appearance,  and  fuppoled  power  of  contrac 
tion,  has,  by  mr-iv  Anatomifts,  been  considered  as  a Mufcje,  and 
C-  lied  Dartos. — This  opinion,  however,  has  of  iate  years  been  re- 
jected. 

The  Cellular  Sublhnce  of  the  Scrotum  involves  each  Teftf- 
cle  finglv,  and  forms  a Septum  or  Partition  between' the  two, 
which  prevents  AT  or  Water  fiom  palling  readily  from  one  fide 
ef  the  Scrotum  to  the  other. 

The  Vejj-'ds  and  Ncr-ves  of  the  Scrotum  are  chiefly  from  thofe  of 
the  neighbouring  parts. 

The  Blood-velTels  are  Branches  of  the  Pudendal  and  Fe- 
moral. 

The  Lymphatics  go  moftly  to  the  Inguinal, — but  fome  o-f  them 
accompany  thofe  of  the  Teftes  to  the  Lumbar  Glands. 

The  anterior  part  of  the  Scrotum  derives  Nerves  from  the 
Lumbar,  and  the  pofterior  from  the  Pudendal  Nerves. 

The  Scrotum  affifts  in  fupporting  and  protecting  the  Teftes. 

Under  the  Scrotum  are  two  Membranes  or  Coats,  proper  to 
each  of  the  Teftes,  the  one  termed'  Vaginalis,  the  other  Albuginea. 

The  "Tunica  Vaginalis,  named  from  its  forming  a (heath,  is  of 
the  fame  nature  with  the  Peritoneum,  being  originally  a Procefs 
of  that  Membrane,  which  in  the  Fcetus  delcend,  with  the  Tefti- 
cle  irom  the  Abdomen. 

It  forms  a fhut  Sac,  which  has  no  communication  with  any  o- 
ther  part. 

It  inclofes  the  Tefticle,  as  the  Pericardium  does  the  Heart,  and 
lies  loofe  every  where,  excepting  behind,  where  it  is  continuous 
with  the  Albuginea. 

It  is  confiderably  larger  than  the  Teftis  which  it  inclofes, 
reaching  as  far  above  and  below  it  as  to  allow  it  a certain  degree 
of  motion. 

It  is  connected  by  its  external  Surface  to  the  Cremafter  Mu  fi- 
de, and  partly,  by  means  of  that,  to  the  inner  Surface  of  the 
Scrotum. 

It  afiifts  the  Cremafter  in  fupporting  the  Teftis,  and,  by  being 
conftantly  moiftened  within  by  a Fluid  exhaled  from  its  Surface, 
and  from  that  cf  the  Tunica  Albuginea,  it  allows  the  Tefticle 
to  move  eafily. 


124 


The  Tunica  Albugineas  fo  called  from  ils  white  colour,  is,  like 
the  former  Coat,  a continuation  of  the  Peritoneum,  and  inveits 
the  Body  of  the  Tefticle  clofely. 

It  is  a thick,  ftrong,  denfe,  and  inelaftic  Membrane,  of  a glif- 
tening  appearance. 

It  is  lemarkably  fmooth  on  the  outfide,  but  internally  it  is 
rough  and  unequal,  adhering  every  where  firmly  to  the  Body  of 
the  Teftis. 

It  covers  both  the  Teftis  and  Epididymis,  connefts  them  to 
each  other,  gives  ftrength  to  them,  and  condudts  their  Veflels 
in  the  manner  the  Mefenteiy  does  thofe  of  the  Inteftines. 

a he  Body  of  the  Teftis  is  of  a yellowifh  colour,  and  has  a Pul- 
py  appearance, — is  of  an  oval  form,  a little  flattened  at  its  outer 
and  inner  Surface  ; — and  frequently  one  Tefticle  is  a little  larger 
ihan  the  other. 


. The  Tell  es  are  placed  obliquely,  with  one  end  upwards  and 
forwards,  and  the  other  end  backwards  and  downwards. 

At  the  outer  and  back-part  of  the  Teftis,  there  is  an  Appen- 
dix named  Epididymis,  from  its  fituation  upon  the  Teftis  or  Di- 
dyrnis,  which  is  inclofed  in  the  fame  covering  with  the  Teftis 
itfelf. 

The  Epididymis  begins  at  the  upper  part  of  the  Tefticle,  im- 
mediately above  the  entry  of  the  Blood-veflels  ; and  this  part  of 
it  being  large  and  of  a round  form,  is  termed  Globus  Major,  or 
Mead  of  the  Epididymis. 

In  its  defcent,  it  becomes  fomewhat  fmaller  and  flatter,  and  is 
attached  behind  to  the  Body  of  the  Tefticle,  where  the  Blood- 
veflels  go  in  ; but  forwards  it  is  loofe,  the  Tunica  Albuginea 
dipping  in  this  place,  and  forming  a Cavity  or  Pouch. 

The  under  part  of  it  becomes  more  firmly  attached  to  the  Bo- 
dy of  the  Tefticle,  and  forms  the  Cauda,  or  Globus  Minor  $ it  is 
then  turned  backwards  upon  itfelf,  after  which  it  fends  out  the 
Excietory  Duff  of  the  Tefticle. 

The  Body  of  the  Teftis  has  numerous  Arteries,  Veins,  Abfor- 
bents,  and  Nerves  ; but  is  principally  compofed  of  a collection 
of  minute,  tender,  elaftic  Filaments,  intricately  convoluted,  term- 
ed T ubuli  Seminijeri,  or  Fa  fa  Seminalia. 

The  Eubitli  Seminijeri  are  difpoled  in  Fafciculi  or  Bundles, 
between  Partitions,  which  are  formed  of  Blood-veflels  and  Cel- 
lular Subllauce. 

Thefe  Septula- begin  at  the  root  or  Nucleus,  fituated  at  the 
back-part  of  the  Tefticle,  fometimes  termed  Corpus  Higbmori- 
anum,  and  extend  in  a radiated  manner  to  the  Tunica  Albu- 
ginea. 

The  Teftis  is  fixed  behind  by  its  Veflels,  which  are  codcCled 
into  a Cord  termed  Spermatic,  but  is  loofe-  and  free  before,  to 
prevent  it  from  being  pinched. 


125 


The  Spermatic  Cord,  properly  fo  called,  extends  from  the  Ring 
of  the  External  Oblique  Mufcl'e  to  theBody  of  the  Tertis,  and  is 
compoled  of  the  Trunks  of  the  different  Vtflfels  belonging  to  the 
Tefticle,  and  of  a quantity  of  Cellular  Sui iltance. — fhe  Cord  is 
covered  by  the  Creniafter  Mufcie  $ and  within  this,  by  the  Cine 
Procefs  of  the  Peritoneum  which  forms  the  Tunica  Vaginal's 
Tertis.  This  part  of  the  Procefs,  however,  is  lb  ncorpcrated 
with  the  common  Cellular  Subftance  of  the  Cord,  as  o appear  to 
form  part  of  it.  : 

The  under  part  of  the  Vagina  of  the  Cord  is  feparated  by  a 
Partition  formed  by  the  upper  end  of  the  Vaginal  Coat  of  the 
Tefticle,  and  by  condenfed  Cellular  Subftance,  fo  that  no  liquor 
can  pafs  ealily  from  the  Cord  to  the  Tefticle,  and  mice  merfa. 

The  Arteries  of  the  Teftes,  termed  A ter  'ue  Spermatic ee,  and 
Arteries  Prepay antes,  arife,  one  on  each  fide,  from  the  fore-port  of 
the  Aorta,  a little  below  he  Renal  Arteries. 

Fhe  Spermatic  Artery  croftes  over  the  Pfoas  Mtifcie  and 
Ureter,  and  defeends,  behind  the  Peritoneum  to  tiie  under  part  of 
the  Abdomen. 

At  the  lower  part  of  the  Abdomen,  it  perforates  the  Ring  of 
the  External  Oblique  Mufcle,  and  paffes  in  the  Spermatic  Corel 
to  the  Tefticle. 

In  its  defeent,  it  gives  blanches  to  the  adjacent  parts,  and  is 
fo  interlaced  with  thoie  of  the  correlponding  Vein,  as  to  have  been 
fupp  feu  by  the  Ancients  to  have  large  lateral  communications 
with  them. 

After  paifing  the  Ring,  it  divides  into  Branches  which  go  to 
the  Eeftis  at  its  porter for  edge.  They  are  partly  difperfed  upon 
the  Epididymis,  but  the  larger  Branches  run  in  a ferpentine  di- 
rection into  the  Subftance  of  the  Eeftis,  where  they  are  minutely 
diftributed  upon  the  Surface  of  the  Seminal  Tubes. 

Belides  the  Spermatic  Artery,  there  is  a (’mailer  one  f.  otn  the 
Hypogaftricy  which  accompanies  the  Vas  Deferens,  and  is  dif- 
perfed along  with  the  other  Artery. 

. The  Veins  are  much  larger  than  the  c rrefponTng  Arte- 
iies,  and  have  feveral  Valves  in  them,  efpecialiy  without  the  Ab- 
dumn. 


I hey  form  a Plexus,  which  accompanies  the  Artery  on  each 
fide,  and  is  (bfnetimes  called  Corpus  P amp y n fo r me,  beiife  com- 
pared to  the  (hoots  of  the  Vine,  or  Corpus  Pyramidale , from  giv- 
ing a Pyramidal  form  to  the  Cord. 

The  Plexus  a Rends  m the  Abdomen,  and  u -on  the  Surface 
0 tu'  1 Mulcle  ; and  abotit  the  part  wheie  it  recedes  f om 

the  Artery,  n forms  a (ingle  Trunk,  whi  h,  in  die  tight  fide, 
tei inflates  in  the  Vena  Cava,  nearly  oppofite  to  the  Artery,  and, 
in  the  left  hde,  goes  into  the  Renal  Vein. 

There  is  alio  a (mall  inferior  Spermatic  Vein,  which  accompa- 
nies ns  Artery,  and  ends  in  the  Hypogaitric  Vein. 


VoL.  11. 


L 2 


126 


Tl'e  Tubuli  Seminiferi  in  the  Body  of  the  Tefiicle  confift  of 
number  ids  extremely  minute  Dufts,  which  are  of  a Cylindrical 
form,  have  no  divifion  into  Branches,  and  when  drawn  out,  are 
found  to  be  feveral  feet  in  length. 

They  are  fit  It  coiicfted  into  Bundles,  between  the  Septulae  of 
the  Tdt  cle,  and  thele  again  into  o.hers  ft.  11  fmaller,  e ch  of  the 
fmallerdSeing.  formed  of  a fimple  Tube,  coiled  up  into  a Conical 
form,'  v it-li  its  Bale  forwards,  and  its  Apex  towards  the  polterior 
edge  of  the  Teftlcie. 

From  the  convoluted  Seminal  Tubes,  an  equal  number  of 
ftraight  VeffeF  art  lent  out  at  the  back,  part  of  the  Tefiicle,  under 
the  name  of  Vafa  Refla. 

At  the  upper  and  back-part  of  the  Tefticle,  the  Vafa  Reffa 
comrr.nnican  , and  form  an  irregular  Plexus  or  Net- Work,  called 
Rete  Vafculcfum  lefts. 

Tlte  Rete  lefts  fends  out  from  twelve  to  eighteen  ftraight 
Tubes,  termed  Vafa  Eferentia , which  carry  the  Semen  from  the 
Tefticle  to  the  Epididymis. 

The  Vafa  Eferentia  foon  become  convoluted,  and  form  Coni- 
cal Bunches,  termed  Coni  Vafculofi. 

The  Coni  Vafculofi  are  firmly  conne&ed  by  Cellular  Subftance, 
and  ate  obferved  by  Dr.  MOi\ro,  in  his  Treatife  De  Eefibus , 
to  compofe  fomewhat  more  than  a third  part  of  the  Epididymis. 

The  Vafcular  Cones  gradually  unite  into  a Angle  Tube,  which 
conftitutes  the  reft  of  the  Epididymis,  and  though  only  about  the 
fize  of  a Hog’s  Briftle,  tranfmits  the  whole  of  the  Semen. 

The  fingle  Tube  becomes  larger  in  irs  coui  fe  and  lefs  convolu- 
ted, and  at  laft,  expanding  its  convolutions,  it  conies  out  greatly 
incteafed  in  fize,  and  almoft  in  a ftraight  direction,  under  the 
name  of  Vac  Deferens. 

Befides  the  Duffs  already  defcribed,  a Vas  Aberrans  is  fome- 
times  obferved,  which  is  one  of  the  Valcular  Cones,  wandering 
off,  and  terminating  in  the  Epididymis  lower  than  ufual. 

At  other  times,  the  fame  kind  of  Veflel  forms  a Procefus  Cecils, 
or  blind  Duff,  with  a dilated  Extremity  which  does  not  com- 
municate with  any  other  part. 


VESICULA2  SEMINALES  AND  PROSTATE  GLAND. 

The  Vefcula  Seminales  are  two  fmall  Pyriform  Receptacles, 
fituated  between  the  under  and  lateral  parts  of  the  Bladder  and 
the  Inteftinum  RefUim,-— about  three  finge.  s-breadth  in  length, 
and  the  third  part  of  that  in  breadth,  ar.d  a little  flattened. 


127 


They  sre  at  a confiderable  diftsnce  from  each  other  behind, 
but  anteriorly  they  converge,  and  become  contiguous,  forming  a 
fliarp  angle. 

Each  of  them  is  compofed  of  a convoluted.  Tube,  with  irregu- 
lar PrSCeJfits,  and  fi  i rounded  by  a quantity  of  tough  Cellular 
Subilance,  and  by  many  Veffcls  and  Nerves. 

Internally,  they  have  a Villous  appea^  ante  and  are  formed  of 
irregular  -€ef/s  which  correspond  .with  the  ^ regularities  on  their 
External  Surface,  and  communicate  freely  with  each  other — 
Their  Hi  ape,  lize,  and  general  appearance,  however,  vary  indif- 
ferent l'ubje£ts,  and  not  unfrequently  in  the  lame  perlon. 

Between  the  Veficuise  Seminales,  the  ends  of  the  Vaia  De- 
ferentia,  now  become  larger  and  Cellular,  pafs  forwards  till 
they  arrive  at  the  Prollrate  Gland,  wlieie  each  Vas  Deferens  joins 
the  Veficula  of  that  fide,  and  communicates  lb  freely  with  it, 
that  inje£led  Fluids  readily  pafs  from  the  one  o the  other. 

From  each  Veficula  Semmalis  and  Vas  Deferens  of  the  fame 
fide,  a fmall  Canal , about  a Finger’s  breadth  in  length,  p-.fles  out 
which  is  firmly  connefted  to  its  fellow,  without  communicating 
with  it,  and  becomes  gradually  fmaller,  piercing,  obliquely,  the 
Predate  Gland,  and  terminating  in  the  under  part  of  the  Neck 
of  the  Bladder. 

The  Orifices  of  thefe  Canals  are  feparated  from  each  other  by 
a Caruncula,  or  round  Projection  of  the  Membrane  of  the  Ure- 
thra, termed  Veru  montauum  , — of,  from  being  bioad  behind  and 
voffriform  before,  it  is  compared  to  the  Head  and  beak  of  the 
Wood  cock,  and  called  Caput  jallinaginis. 

'Fire  Veiiculae  Seminales  are  commonly  confidered  as  Refcrvoirs 
of  the  Semen,  receiving  it  from  the  Vafa  Dcferentia,  and  after- 
wards,— by  a power  inherent  in  themfelves,  affifted  by  the  aftisn 
of  the  neighbouring  Mul'cles,  particularly  of  the  Levatores  Ani, 
— propelling  it  to  the  Urethra. 

The  Semen  is  prevented  from  paffing  into  the  Bladder,  the 
opening  from  it  being  (hut  while  that  Fluid  is  expelled. 

Various  experiments  have  been  made  on  the  Veficula:  Semi- 
nales by  the  late  Mu.  Hunter,  from  which  he  was  of  opi- 
nion, that  they  are  not  Refervoirs  of  Semen,  but  Glands,  fe- 
creting  a particular  Mucus  ; — that,  with  oilier  parts,  they  are 
fubfervient  to  the  purpol'es  of  Generation  and  that  the  Bulb  of 
the  Urethra  is  the  receptacle  of  the  Semen  in  which  it  is  ac- 
cumulated previous  to  its  ejeffion. 

The  Profiate  Gland,  named  from  its  fituation  before  the  Vefi- 
culaea  Sem  nales,  lies  mimediately  behind  the  under  end  of  the 
Symphyfis  of  ihe  Pubis,  and  reds  upon  the  Inteltinum  Reftum. 

It  furrounds  and  clofely  embiaces  the  Neck  of  .the  Bladder,  or 
beginning  of  theUretlua;  but  the  greater  part  of  it  is  placed 
pofteriorly  and  laterally,  having  a Lobe  projefting  on  each  fide. 


1 28 


It  is  about  the'fiz'e'of  a Walnut,  and  of  the  figure  of  a Spanifii 
Chefiuit,— or  it  refetnblesa  Heart  as  commonly  painted  on  Play- 
ing-cards, with  the  Bafe  towards  the  Bladder,  and  the  Point 
towards  the  Penis. 

It  has  a Spongy  Subdmce,  but  is  one  of  the  firmed  Glands  of 
the  Bvody,  and  generally  fends  out  ten  or  twelve  Duds,  which 
open  obliquely  at  the  ’beginning  of  the  Urethra,  at  the  fides  ol 
the  Caput  Galbnagtn's,  and  neat  the  teimination  of  the  Seminal 
Du£fs. 

From  the  Dufls  of  the  Proflate  Gland,  a thin  white  Liquor 
is  diicharged,— b om  th  fame  caufes,  and  at  the  fame  time  with 
the  Semen, — into  the  Uiethra,  and  is  fuppofed  to  bj  ufeful  in 
the  procefs  of  Generation  ; — or,  according  to  fome  Authors, 
this  Fluid  facilitates  the  paflage  of  the  Semen  through  the 
Urethra. 

The  Blood -veffels,  Abforbents,  and  Nerves  of  the  Veficulas 
Seminales  and  Prodate  Giand,  ate  in  common  with  thofe  of  the 
parts  which  furround  them. 

P E N I S. 

The  Penis , which  has  obtained  a variety  of  other  names, 
fuch  as  Merfibrutn  Virile , Meutula , Sec.  confilis  of  three  S .ongy 
Subdances,  two  of  which  form  the  upper  pait  and  fid  s,  or  Body 
of  the  Penis  and  are  tetmed  Corpora  Caver  noj'a  Penis,  the 
third  lunounds  the  Urethra,  and  has  the  name  of  Corpus  Spon- 
giofum  Urethras. 

The  Penis  is  covered  with  a continuation  of  the  common  inte- 
gument's, which  are  thinner  than  eii'ewhere,  and,  indead  of  Fat, 
there  is  as  in  the  Scrotum,  a Reticular  Subdance  only  under  the 
Skin. 

At  the  anterior  extremity  of  the  Penis,  the  Integuments  foim 
a loofe  fold,  te'rned  >' repuce,  which  is  connected  to-  the  .-inter. or 
and-  under  pat t,  or  Glaus  of  the  Penis,  by  a triangular  fold, 
called  Pr.enum  Preputii. 

The  t.orpora  Cavernofa  Penis  refemble  two  equal  but  irregular 
Cylinders,  clofely  applied  to  the  i.des  of  each  other,  and  each 
covered  by  a droira,  eitdtic,  Ligamentous  Sheath,  the  Fibres  ot 
which  run  in  a tranfveife,  and  pattly  in  an  oblique  direftion. 

They  ar-ife  one  on  each  fide,  by  two  bitr.J  Conical  extremities, 
calhd  their  Crura,  from  the  inner  part  ot  the  Crura  of  tire  Ofla 
Ifchta  and  Offa  Pubis,  to  both  of  which  they  are  very  firmly 
connefled  by  Ligamentous  Snbi-ances. 

At  tire  under  part  of  the  S . mphyfis  of  the  Pubis,  they  are  uni- 
ted to  each'  other,  and  continue  fo  till  they  teach  the  Glands, 
where  the)  ten  bifnate  in  a.i;o  bided  exit  entity; 

At  the;  upper  mart  of  i lie  root  u uhe  .Pen's,  the  L'n  amcntoiis 
Sheath  of  the  Corpora  Cavernoia  fends  up  a Proeels  ol  a triungu- 


129 


lar  form,  to  be  connected  to  the  Syrnphyfis  of  the  Ofla  Pubis, 
under  the  name  of  Ligamentum  Sufpenforium,  by  which  the  Body 
of  the  Penis  is  fup  ported,  and  prevented  from  prefling  too  much 
upon  the  Scrotum. 

The  Corpora  Cavernofa  leave  a Groove  above,  for  the  princi- 
pal Vein  of  the  Penis,  and  a Channel  below  for  the  Cavernous 
Subilance  of  the  Urethra. 

The  internal  fubltance  of  the  Corpora  Cavernofa  ccnfifts  of 
loofe  reticular  Plates,  foinewhat  Gmilar  to  the  Cancelli  in  the  ends 
of  long  Bones,  and,  like  them,  readily  communicating  with 
each  other. 

Upon  the  Cells  of  the  Corpora  Cavernofa,-  the  Arteries  are  plen- 
tifully difperfed,  and  open  freely  into  them,  the  Blood  of  the 
Arteries  tinging  the  Cells  in  the  relaxed  date  of  the  Penis,  and 
filling  them  completely  when  it  is  difltended. 

The  Corpora  Cavernofa  are  united  to  each  other  by  a Septum 
or  Partition,  formed  by  a continuation  of  the  Elaitic  Ligament 
which  covers  thefe  Bodies. 

The  Septum  Penis  is  compofed  of  Cords,  extending,  nearly  in 
a parallel  direction,  from  the  Dorfum,  or  upper  part  of  the  Penis, 
to  the  Corpus  Spongioi'um  Urethrae. 

Between  the  different  Cords,  FiJJ'ures  are  left,  through  which 
the  Blood,  or  an  inje.fted  Fluid,  palfes  without  obftruftion  from 
one  of  the  Corpora  Cavernofa  to  the  other. 

The  Corpus  Spongiofum  Urethrae  is  fituated  under  and  between 
the  Corpora  Cavernofa  Penis,  but  projefts  confiderably  beyond 
them. 

It  begins  a little  behind  the  part  where  the  Corpora  Cavernolu 
are  united,  adheres  to  them  by  condenfed  Cellular  Subltance,  and 
terminates  at  the  anterior  extremity  of  the  Penis. 

It  has  an  external  covering  fimilar  to  that  of  the  Corpora  Ca- 
vemofa  Penis,  but  more  delicate  and  more  of  a Membranous  ap- 
pearance. 

The  pofterior  part  of  the  Corpus  Spongiofum  is  dilated  into 
a longitudinal  Prominence,  of  a Conical  form,  fituated  within  the 
Skin  of  the  Perineum,  and  termed  Bulb  of  the  Urethra.  It  ex- 
tends from  the  root  of  the  Penis  to  near  the  Anu~,  projefts  mod 
towards  the  under  and  back  pu  t,  and  is  divided  anteriorly  by  a 
.Septum. 

The  Corpus  Spongiofum  is  continued  along  the  under  part  of 
the  Coi  pora  Cavernofa,  and  at  the  end  of  thefe  expands  into  the 
Sublhmce  called  Gians  Penis,  which  covers  and  indoles  the  ends 
of  the  Corpora  Cavernofa. 

The  Gians  or  Nut,  named  from  its  refemblance  to  an  Acorn, 
is  feparated  from  the  Corpora  Cavernofa  by  a continuation  of  the 
Ligamentous  Sheath  which  covers  them,  and  is  encircled  at  its 
pofterior  part  by  a prominent  margin,  called  Corona  Glandis,  be- 
hind which  is  a Cervix  or  Neck. 


130 


The  Surface  of  the  Gians  is  covered  with  a Plexus,  chiefly  of 
Venous  Veffels,  and  with  Nervous  Papilla ?,  which  give  it  its  l'en- 
fibility  ; and  thel'e  are  incloi'ed  in  a fine  Membrane  continued 
from  the  infide  of  the  Prepuce. 

About  the  Cervix  and  Corona  of  the  Gians,  are  many  Follicles, 
termed  Glandules  Odorij'tree,  which  di  fell  urge  a Sebaceous  Mat- 
ter, to  preferve  the  fenflbility  of  the  Gians,  and  allow  the  Pi e- 
puce  to  move  backwards  and  forwards  upon  it  with  facility. 

The  Internal  Stru&uie  of  the  Bulb  of  the  Urethra  and  Gians 
of  the  Penis,  is  of  the  fame  nature  with  that  of  the  Corpora 
Cavernofa  ; and  the  Internal  Strufture  of  the  reft  of  the  Corpus 
Spongiolum  differs  from  that  of  the  Corpora  Cavernofa  only  in 
this,  that  the  Ceils  are  fmaller  and  of  a more  delicate  texture. — 
Some  Anatoinifts  confider  the  greater  part  of  the  Corpus  Spon- 
giofum  as  merely  a Plexus  of  convoluted  Veins. 

The  Urethra,  named  from  the  Uiine  paflinj  through  it,  is  a 
long  Canal,  the  Diameter  of  which  is  nearly  equal  to  that  of  a 
writing-pen.  It  begins  at  the  under  and  fore-part  of  the  Bladder, 
runs  through  the  Corpus  Spongiolum,  and  terminates  in  the 
point  of  the  Penis  by  a longitudinal  Orifice. 

At  its  origin,  it  defeends  a little,  and  then  paffes  forwards, 
under  the  Symphyfis  of  the  OfiTa  Pubis,  to  which  it  is  clofely 
connefted  by  Cellular  Subftance  : It  then  afeends  at  the  under 
and  fore-part  of  the  Offa  Pubis,  varying  in  the  remainder  of  its 
courfe,  according  to  the  different  degrees  of  relaxation  ordiften- 
lion  of  the  Cells  of  the  Penis. 

There  are  commonly  three  Dilatations  in  the  Urethra  ; one  of 
which  is  at  the  Proftate  Gland,  the  fecond  in  the  Bulb  of  the 
Urethra,  and  the  third  about  the  beginning  of  the  Gians. 

In  general,  it  has  alfo  the  fame  number  of  J. light  Contraptions  ; 
the  firtt  at  its  origin  from  the  Bladder,  the  fecond  between  the 
point  of  the  Proftate  Gland  and  Bulb  of  the  Urethra,  and  the 
third  at  the  point  of  the  Gians. 

Between  the  point  of  the  Proftate  Gland  and  part  where  the 
Urethra  pene’.  rates  the  Corpus  Spongiofum,— including  nearly  the 
fpace  of  a Finger’s -bi  eaarh, — i he  Urinary  paff.,ge  is  entirely  Mem- 
branous, and  covered  only  with  the  common  Cellular  Subftance. 

At  the  upper  fide  of  the  Bulb,  the  Urethra  enteis  the  Corpus 
Spongiolum,  m which  it  i incloled  to  its  termination  in  the  point 
of  the  Penif. 

The  infide  of  the  Urethra  is  lined  by  a very  Vafcular  and  fenfi- 
ble  Membrane,  wh.ch  is  obferved  to  poffefs  a certain  degree  of 
contradf  il  ity,  and  is  therefoie  prefumed  by  leveral  Anatom  ills 
to  be  endowed  with  Mufculnr  F bres. 

Between  the  Corpus  Spongiofum  and  Membrane  which  lines 
the  Urethra,  el'pecially  towards  the  Septum  of  the  Penis,  nume- 
rous Lacunae  of  different  fizes  are  fi  uated,  one  or  two  ot  which 
in  particular,  next  the  Glands,  are  often  confiderably  larger  that) 
the  left. 


131 


They  run  in  a longitudinal  direction  from  behind  forward,  and 
perforate  the  Urethra  bv  Orifices  large  enough  to  admit  a Brittle. 
— They  dif'cha.ge  a bland  Mucus  for  the  defence  of  the  Uie- 
thra. 

Belides  the  Lacunae,  two  fmall  bodies,  each  about  the  fize  of 
a Garden-pea,  3re  frequently  met  with,  and  are  termed,  from 
their  difeoverer,  Covvper’s  Glands. 

They  are  fituatcd  at  the  fides  of  the  Membranous  part  of  the 
Urethra, — between  its  Bulb  and  the  point  of  the  Prolfate  Gland, 
— and  covered  by  the  Accelerator  Mufcles. 

When  prefent  they  are  o'  ferved  to  d fcharge  from  their  Dufls 
into  the  Urethra,  a Fluid  which  is  liippofed  to  ferve  the  fame 
purpofe  with  that  of  the  Lacunae. 

The  Arteries  of  the  Penis  are  chiefly  from  the  Pudicae  Com- 
munes, which  are  Branches  of  the  Internal  Iliacs,  and  partly 
from  the  Femoral  Arteries. 

Each  of  the  Pudic  Arteries  having  paffed  out  of  the  Pelvis, 
through  the  great  Notch  of  the  Os  ilium,  runs  between  the 
Sacro-Sciatic  Ligaments  to  the  inner  fide  of  the  Tuber  Ifchii, 
from  which  it  paffes  along  the  Crus  of  that  Bone,  and  of  the  Os 
Pubis,  to  the  root  of  the  Penis. 

In  its  coutfe,  it  funufhes  Branches  to  the  adjacent  parts,  and 
afterwards  gives  off  three  principal  Branches,  which  belong  to 
the  Penis  : — One  of  thefe  goes  to  the  Bulb  of  the  Uiethra,  to  be 
difperfed  in  the  Corpus  Spongiofum  ; — the  other  two,  which  are 
larger  than  the  former,  go  to  the  Body  of  the  Penis,  one  of  them 
penetrating  its  Crus,  and  running' in  the  centre  of  the  Corpus 
Cavernofum  ; the  other  paffing  between  the  Symphyfis  Pubis  and 
joining  of  the  Crura  Penis,  and  extending  along  the  Dorftim  as 
tar  as  the  Corona  Glandis. 

The  Branches  of  the  Femoral  Artery  to  the  Penis  communi- 
cate with  thofe  of  the  former,  and  are  chiefly  difperfed  upon  the 
Integuments. 

The  Arteries  of  the  Penis  are  divided  into  minute  Ramifica- 
tions, which  communicate  with  each  other,  and  with  their  fellows 
on  the  oppoiite  fide  and  terminate  partly  in  the  correfponcling 
Veins,  and  partly  in  the  Cells  of  the  Penis. 

The  Veins  arife,  fome  from  the  extremities  of  the  Arteries,  and 
others  by  large  open  Mouths  from  the  Cells  of  the  Penis. 

The  greater  number  of  the  Veins  unite  into  a Trunk,  called 
Vena  Magna  Penis,  which  runs  in  the  fuperior  Groove  formed  by 
the  union  of  the  Corpora  Cavernofa,  and  is  furniflied  with  Valves, 
and  with  thick  Alton g Coats. 

The  Vena  Magna,  at  the  under  end  of  the  Symphyfis  Pubis, 
feparates  into  Right  and  Left  Plexus,  which  pafs  to  the  corre- 
fponding  Iliac  Veins. 

To  an  oblfrudf  on  of  the  courfe  of  the  Blood  through  the 
Veins,  by  the  pte fibre  of  the  Mufcles  at  the  root  of  the  Penis, 


;>  "f  . 


132 


together  with  an  increafed  influx-through  the  Ai'terids,  is  owing 
that  accumulation  ot  Blood  in  the  Corpora  Cavernofa,  which 
occafions  a diltenfion  of  the  Penis. 

The  relaxation  of  the  Penis  happens  from  the  caufes  which 
produced  the  dlftenfion  being  removed  ; — The  Elaftic  Ligamen- 
tous Membrane  which  covers  the  Penis  again  forcing  the  Blood 
from  the  Cells  into  the  Veins. 

Upon  the  Surface  of  the  Penis,  there  are  fmall  Superficial 
Veins,  which  communicaie  with  thofe  deeper  feated,  and  com- 
monly terminate  by  one  or  more  Branches  in  the  Veins  at  the 
top  of  the  Thighs 

Thefe  Branches  affift  in  carrying  on  the  circulation,  and  return 
part  of  the  Blood  during  the  diftenfion  of  the  Penis. 

Of  the  Lymphatics  of  the  Penis,  thofe  from  the  Prepuce  and 
Skin.,  in  genera],  go  to  the  right  and  left  Inguinal  Glands,  while 
the  Lymphatics  from  the  Gians  and ’Body  of  the  Penis  accom- 
pany the  Arteries  into  the  under  part  of  the  Pelvis. 

The  Nerves  of  the  Penis  are  large  in  proportion  to  the  fize  of 
thdt  Organ.  They  come  from  the  Hypogaffric  Plexus,  and  prin- 
cipally from  the  laft  Sacral  Nerves,  and  are  diftributed  chiefly  up- 
on the  Ligamentous  Sheath  which  inclofes  the  Corpora  Cavernofa. 

They  are  fituated  upon  the  Doifum  of  the  Penis,  more  laterally 
than  the  Arteries  which  lie  between  them  and  the  principal  Vein. 

For  the  Mufcles  of  the  Penis,  fee  Part  IT. 

The  Penis  ejeJls  the  Semen  into  the  Vagina,  and  ferves  for  the 
conveyance  of  the  Urine  from  the  Bladder. 


■oooooooo-csoooooooo 


OF  THE 

ORGANS  OF  URINE  AND  GENERATION 


IN  THE  FEMALE. 


The  Kidneys,  Renal  Glands,  and  Ureters,  have  the  fame  fitu- 
ation  and  llrufl'ure  as  in  the  Male. 

The  Bladder  has  alfo  the  fame  fituation  behind  the  Ofla  Pubis, 
but  rifes  higher  when  it  is  in  the  diftended  (late. 

It  is  propoi  tionally  larger  than  the  Bladder  of  the  Male,  and 
is  broader  from  one  fide  to  the  other,,  corretponding  to  that  part 
of  the  Cavity  of  the  Pelvis  to  which  it  belongs. 


133 


The  Urethra  is  much  fhorter, — being  fcarcely  two  inches  in 
length, — and  ftraighter  than  in  the  Male,  having  only  a flight 
bend  downwards  between  its  extremities. 

It  is  produced  from  the  mod  depending  part  of  the  Bladder, 
has  no  proftate  Gland,  but  is  furnilhed,  as  in  the  Male,  with 
Lacurue , which  open  into  it,  and  difcharge  a Mucus  to  defend 
it  from  the  Urine. 

The  Parts  of  Generation  in  the  Female  (which  are  here  fup- 
pofed  to  be  in  the  unimpregnated  Hate)  are  divided  into  Internal 
and  External.  The  former  confift  of  the  Uterus  and  its  Appen- 
dages, the  latter  are  thofe  which  are  feen  without  any  Difledlion. 

Internal  Parts. 

The  Uterus , Matrix,  or  Womb,  is  a hollow  Vifcus,  lituated 
in  the  Peivis,  in  the  Hypogaftric  Region,  between  the  Bladder 
and  Reftum,  with  which  it  is  connected. 

It  is  of  a triangular  figure,  and  a little  flattened  before  and  be- 
hind, but  more  fo  anteriorly  ; is  large  above,  fmall  below,  and 
has  two  angles  at  its  upper  and  lateral  parts,  called  Corners  of 
the  Uterus. 

It  is  diftinguilhed  into  Fundus,  or  tipper  part,  which  includes 
the  fpace  above  the  infection  of  the  Fallopian  Tubes,  the  Body 
-or  middle,  and  Cer-uix  or  under  part,  the  two  laft  being  nearly 
of  equal  length. 

The  extent  and  figure  of  the  Uterus  varies  confiderably  in  dif- 
ferent fubjedts.— In  Women  who  have  never  been  pregnant,  it  is 
commonly  about  two  inches  and  a half  in  length,  from  one  inch 
and  a half  to  two  inches  in  breadth  at  the  Fundus,  and  about 
half  as  broad  at  the  Cervix. — It  is  near  an  inch  in  thicknefs,  and 
is  la'ger  in  Women  who  have  borne  Children,  thanin  the  Virgin 
ftate. 

The  Cavity,  like  the  external  part  of  the  Uterus,  is  of  a tri- 
angular jorm,  but  is  fmall  in  proportion  to  the  fize  of  the  Organ, 
—being  fcarcely  capable  of  containing  the  Kernel  of  an  Almond, 
— and  has  its  fides  clofely  applied  to  each  other. 

It  is  covered  externally  through  its  whole  length,  with  a fmooth 
polifhtd  Coat,  continued  from  the  Peritoneum,  which,  at  the 
under  part  of  the  Cervix,  is  refledled  forwards  upon  the  Bladder, 
backwards  over  the  Redtum,  and  laterally  towards  the  Sides  of 
the  Pelvis. 

Its  Subftance  is- of  a compadl,  Cellular,  and  Flelhy  nature, 
and  plentifully  fupplied  with  Blood-velfels  : The  Flelhy  Fibres, 
however,  are  feen  diftindlly  only  in  the  Gravid  Uterus. 

It  is  remarkably  Vafcular  in  its  Body,  lefs  fo  in  its  Cervix,  and 
is  nearly  of  the  fame  thicknefs  throughout,  excepting  at  its  Cor- 
ners, where  the  Uterine  or  Fallopian  Tubes  terminate. 

Vol.  II.  M 


134 


It  is  lined  with  a fine  and  very  vafcular  Membrane,  of  a fome- 
what  Porous  and  Villous  appearance,  in  which  the  Arteries  ter- 
minate which  difcharge  the  Menftrual  Fluid. 

The  Cavity  of  the  Cervix  has  two  fmall  Longitudinal  Lines 
projefting  in  it,  one  in  the  anterior,  the  other  in  the  pofferior 
part,  on  each  fide  of  which  are  numerous  Ruga. 

The  Ruga  run,  in  an  obliquely  tranfverfe  direflion,  and  arc 
formed  not  only  of  the  inner  Membrane,  but  alfo  by  the  Fibres 
which  compofe  the  Body  of  the  Uterus. 

Between  the  Rugae  are  many  fmall  Follicles,  which  difcharge  a 
Mucus  for  lubricating  the  parts  near  which  they  are  placed 
Some  of  them,  being  of  a roundifh  form,  were  mi  (taken  by  Na- 
both for  Female  Ovula, 

The  under  part  of  the  Cervix  projects  into  the  Vagina,  fome- 
what  in  form  of  the  Gians  Penis,  and  is  perforated  by  a tranf- 
verfe (lit,  termed  Os  Tinea: , from  its  fuppofed  refemblance  to  the 
Mouth  of  the  Tench  Fifli. 

The  Os  Tinea,  in  an  Uterus  which  has  never  been  impreg- 
nated, is  about  the  fize  of  the  orifice  of  the  Urethra  in  the  Male, 
but  nearly  twice  as  laige  in  the  Uterus  of  a Woman  who  has 
borne  Children. 

Itisfmooth  on  its  external  fnrface,  is  placed  obliquely  in  a di- 
^reftion  towards  the  back-part  of  the  Vagina,  and  is  (unrounded 
with  feveral  Mucous  Follicles. 

Appendages  of  the  Uterus. 

The  Appendages  of  the  Uterus,  are  the  Broad  and  Round  Liga- 
ments, the  Onjaria,  the  Fallopian  Tubes,  and  the  Vagina. 

The  Ligamenta  Lata,  termed  fometimes  Ala  Vefpertilionis, 
from  their  refemblance  to  the  Wings  of  a Bat,  are  two  Membra- 
nous produ&ions,  or  Doublings  of  the  Peritoneum,  fent  from  the 
edges  ot  the. Uterus  and  pofterior  extremity  of  the  Vagina,  to  be 
fixed  to  the  fides  of  the  Pelvis. 

Along  with  the  Uterus,  they  feparate  the  Pelvis  into  anterior 
and  pofterior  Cavities,  and  are  themfelves  divided  into  large  and 
fmali,  or  anterior  and  pofterior  Alse  or  Pinions. 

They  contain  and  fupport  the  Ovaria  and  Uterine  Tubes,  with 
part  of  the  Spermatic  and  Uterine  Vefi’els  and  Nerves.  They 
likewifir  inclofe  a portion  of  the  Ligamenta  Rotunda,  &c.  con- 
ned! the  Uterus  to  the  fides  of  the  Pelvis,  and  affift  in  retaining  it 
in  its  place.  In  the  time  of  Geftation  they  become  effaced,  by 
furniftiing  the  Uterus  with  part  of  its  external  covering. 

The  Ligamenta  Rotunda  are  two  long  and  (lender  Cords,  ccm- 
pofed  of  Veflels  and  Ligamentous  Fibres,  arifing  from  the  Cor- 
ners of  the  Uterus,  immediately  before  and  below  the  Fallopian 
Tubes,  from  which  they  defeend  obliquely  in  the  Ligamenta 
Lata,  diminishing  a little  in  their  courfe  towards  the  Groins. 


135 


They  pais  through  the  Rings  of  the  Abdominal  Mufcles,  in 
the  fame  manuer  as  the  Spermatic  Cords  do  in  the  Male,  and  are 
afterwards  inferted  by  feparate  Branches  into  the  upper  and  late- 
ral parts  of  the  Pudendum. 

They  affift  the  Ligamenta  Lata  in  preferving  the  equilibrium 
of  the  Uterus. 

The  0*varia,  anciently  called  Tefies  Muliebres,  are  fituated  at 
the  tides  of  the  Fundus  of  the  Uterus,  about  an  inch  diftant 
from  it,  and  are  contained  in  the  pofterior  Pinions  of  the  Liga- 
menta Lata,  which  form  a Coat  to  them  fimilar  to  the  Tunica  Al- 
buginea Tellis. 

The  Ovaria  are  plain  above,  and  prominent  and  femi  oval  be- 
low, flattened  at  their  anterior  and  pofterior  Surfaces,  and  the 
ftze  of  each,  when  in  a ftate  of  the  grealelt  maturity,  nearly  equal 
to  half  of  the  Male  Tellicle. 

They  are  large,  uniform,  and  fm'both,  in  the  vigour  of  life,  but 
become  finall,  unequal,  and  (hrivelled,  in  Old  Women,  or  in  thofe 
who  have  borne  many  Children. 

They  are  attached  to  the  Uterus  by  the  Ligamenta  Lata,  and 
by  two  fmall  Cords,  termed  Ligamenta  Rotunda  Ovarii,  which 
were  miltaken  by  the  Ancients  for  Vafa  Deferentia,  carrying  a 
fecreted  Liquor  to  the  Uterus. 

They  ate  compofed  internally  of  a loofc  whitifli  Cellular  Sub- 
ftance,  intermixed  with  Vefiels  and  Nerves,  and  contain  a num- 
ber of  fmall  Veficles,  called  Ova,  filled  with  a limpid  Fluid, 
which  partakes  of  the  qualities  of  the  White  of  an  Egg. 

Thefe  Veficles  differ  much  in  fize  in  the  fame  Ovarium 
largefl  of  them  are  feldom  equal  to  the  fize  of  a fmall  Garden- 
pea. 

The  number  of  Ova  is  differently  eftimated  by  different  Ana- 
tomifts, — from  ten  to  twenty  and  upwards  having  been  found  in 
one  Ovarium. 

According  to  experiments  made  by  Mr.  Hunter,  it  is  afcer- 
tained, — that  the  number  of  originally  exifting  Ova  in  each  Ova- 
rium, whether  that  number  be  greater  or  fmaller,  may  be  dimi- 
nifhed,  but  cannot  be  increafed. 

The  Ovana  ferve  for  the  nomifhment  of  the  Ova,  which  con- 
tain the  rudiments  of  the  Foetus. 

The  Uterine,  or  Fallopian  Tubes,  compared  in  fhape,  by  Fal- 
lopius, to  that  of  a Trumpet,  are  two  Conical  and  Vermiform 
Canals,  attached  to  the  Corners  or  the  Uterus,  and  terminating 
in  it,  each  by  a fmall  Opening  which  fcarcely  admits  the  entrance 
of  a Briftle. 

They  become  gradually  larger  in  them  pafi'age  towards  the  fides 
of  the  Pelvis  : Near  their  outer  extremity,  they  are  convoluted 
and  coniiderably  dilated,  but  are  afterwards  fuddenly  contrafled, 
and  terminate  by  open  Months  fufficiently  large  to  admit  the  point 
et  a Goofe-quil).  r 


136 


Their  outer  ends  are  free  and  fluctuating  in  the  Pelvis,  and  ex- 
pand into  many  irregular  jagged  or  pointed  extremities,  called 
i'imbria,  which  are  conliderably  longer  at  one  fide  of  the  Tube 
than  the  other. 

They  are  commonly  upwards  of  a hand-breadth  in  length, 
and  contained  in  a Doubling  of  the  Ligamenta  Lata.— In  their 
natural  filiation,  they  lie  near  the  Ovaria  ; but  when  drawn  out 
and  extended,  are  a Finger's-breadth  diftant  from  them. 

The  itruCture  of  the  Tubes  is  nearly  the  fame  with  that  of  the 
Uteius,  and,  like  it,  they  are  capable  of  dilatation  and  contraction  : 
Their  Inner  fide,  however,  has  a different  appearance,  being  fur- 
nifhed  with  many  (mall  longitudinal  Plicae,  which  are  moll  con- 
Ipicuous  towards  the  outer  extremities. 

The  Tubes  are  fuppofed  to  convey  the  prolific  part  of  the  Male 
Semen  from  the  Uterus  to  the  Ovaria,  in  order  to  foecundate  the 
Ova  ; and  by  grafping  that  part  of  the  Ovarium  where  the  ripeft 
Ovum  is  fituated,  to  carry  the  Ovum,  according  to  fome  Au- 
hors,  or  its  contents  only  according  to  others,  to  be  mixed 
with  the  Male  Semen,  and  to  be  lodged  in  the  Cavity  of  the 
Uterus. 

The  Vagina  is  a Membranous  Canal,  which  extends  from  the 
Neck  of  the  Uterus  to  the  opening  of  the  Pudendum. 

It  is  fituated  behind  the  Bladder  and  Urethra,  ar.d  before  the 
under  part  of  the  Inteftinum  ReCtum,  to  each  of  which  it  is  clofely 
connected  by  Cellular  Subftance. 

It  begins  a little  above  the  Internal  Orifice  of  the  Uterus,  but 
reaches  higher  at  the  pofterior  than  anterior  part ; from  which 
circumftance,  together  with  a flight  Curvature  it  has  backwards, 
the  Canal  is  found  to  be  longer  in  its  pofterior  than  anterior 
Surface. 

From  the  Os  Tine  as,  it  paffes  downwards  and  forwards,  and 
terminates  between  the  Labia  Pudendi,  the  Axis  of  the  Vagina 
forming  a confide) able  Angle  with  that  of  the  Uterus. 

The  dimenfions  of  the  Vagina  correfpond  with  the  fize  of  the 
Penis  in  the  Male  ; but  vaiy  according  to  the  temperament  if 
the  Body,  and  become  larger  in  Women  who  have  borne  Chil- 
dren. 

The  Body  of  the  Vagina  is  compofed  of  thick,  ftrong,  Mem- 
branous parts,  and  furnifhed  internally  with  numerous  irregular 
Rug#  or  Wrinkles,  ar.d  Nervous  Papilla,  the  former  of  which 
confiderably  diminifh  the  capacity  of  the  Canal,  and  the  latter  add 
to  its  fenfibility. 

The  Ruga  run  in  a tranfverfe  direction,  and  are  fodifpofed  as 
to  divide  the  Vagina  into  anterior  and  pofterior  Columns,  which 
join  together  laterally,  and  produce  a Raphe  or  Suture  at  the 
right  and  left  fides. 

They  aie  deepeft,  largeft,  and  moft  crowded  upon  the  anterior 
and  to  winds  the  outer  part  of  the  Vagina;  are  moft  confpicuous 


137 


in  Virgins,  lefs  fo  in  married  Women,  and  become  more  and  more 
effaced  in  thole  who  have  borne  Children. — The  Rugae  facilitate 
the  diitenfion  of  the  Vaginajluring  Child-birth. 

The  whole  extent  of  the  Vagina,  particularly  towards  its  outer 
extremity,  isfuniifhed  with  linall  Follicles,  the  orifices  of  which 
can  frequently  be  fein. 

Tiiey  fupply  a Mucus,  with  which  the  Canal  is  always  lubri- 
cated, and  which  is  difeharged,  in  time  of  Coition,  in  fuch  abun- 
dance, as  to  have  been  formerly  confidered  as  an  emilfion  of  Fe- 
male Semen. 

The  outer  end  of  the  Vagina  is  covered,  on  effcfi  fide,  by  a 
Subftance  compofed  of  Blood- velfels.  and  Cells  fimiiarto  thole  of 
the  Penis,  and  defcribed  by  De  Graaf  under  the  name  of  Plex- 
us Reteformis , and  by  later  Anatomiits  under  that  of  Corpus  Ga- 
* vernof&m  Fagind. 

The  Corpora  Caasernofa  are  covered  by  the  Sphinfter  Vaginas 
Mufcle,  the  aftion  of  which,  joined  to  the  Dilatation  of  thefe 
Bodies,  ferves  to  contrail  the  entry  of  the  Vagina  in  the  time  of 
Coition. 

The  Ufe  of  the  Vagina  is  to  receive  the  Penis  and  Semen,  and 
to  convey  from  the  tferus  the  Menltrual  Flux,  the  Foetus,  the 
Secund.nes,  and  the  Lochia. 

The  Uterus,  with  its  Ligaments,  Ovaria,  and  Uterine  Tubes, 
are  fupplied  with  Blood  from  the  Spermatic  and  Uterine  Ar- 
teries. 

The  Spermatic  Arteries  a ife  from  the  Aorta,  as  in  the  Male, 
and  run  in  the  Ligamenta  Lata,  to  be  difperfed  upon  the  Ovaria 
and  Uterine  Tubes,  and  afterwards  upon  the  Uterus  itlelf. 

The  Uterine  Arteries  are  derived  from  the  Internal  lliacs,  and 
are  much  larger  than  the  Spermatics.  They  direct  their  courl'e, 
fil'd  to  the  under  part  of  the  Uterus,  after  which  they  afeend  along 
its  edges,  and  near  its  upper  part  join  the  Spermatic  Arteries. 

From  the  Uterine  chiefly,  and  partly  from  the  Spermatic  Ar- 
teries, many  I'm  ,11  Branches  are  furnilhed,  which  run  in  a Ter- 
pentine manner,  and  communicate  with  their  fellows  in  the  oppo- 
fite  fides  of  the  Uteius. 

The  Vagina  is  fupplied  with  an  Artery  on  each  fide. — termed 
Paginal., — from  the  Uterine,  and  with  linall  Branches  from  the 
Umbilical,  M ddle  Htemorrhoidal,  and  Pudendas  Communes. 

The  Spermatic  Feins  have  the  fame  termination  as  in  the  Male, 
but  are  coniiderably  larger.— -The  other  Veins  run  into  the  Inter- 
nal Iliac. 

The  Lymphatics,  like  the  Blood-velfels,  run  alfc-  in  two  Sets. 
Thole  of  the  one  fet  accompany  the  Spermatic  Blood-vcflels,  and, 
like  the  Abforbents  of  the  Telles  in  the  Male,  go  to  the  Lumbar 
Glands.  Thole  of  the  other  correlpond  with  the  Hypogaftric 
Blood-velfels,  and  terminate  in  the  Glands  at  the  lateral  parts  of 
the  Pelvis. 

Vol.  [I.  M 2 


133 


Tile  Nerves  are  from  the  Sacral  and  Great  Sympathetics- 
The  Ufe  of  the  Uterus  is, — to  receive  from  the  Ovaria,  by 
means  of  the  Fallopian  Tubes,  the  Rudiments  of  the  Foetus, — 
to  nourifh  it,  and,  after  bringing  it  to  maturity, — to  expel  it 
through  the  Os  Internum  Uteri  and  Vagina.— From  the  Inner 
Surface  of  the  Uterus,  the  Menftrual  Evacuation  is  alfo  dif. 
charged. 


The  Internal  Parts,  called  Pudendum  or  Vulva,  are  formed 
of  two  prominent  fides,  termed  Labia  Pudendi,  Labia  Externa, 
or  Alee  MTRbres.  Thefe  are  contiguous,  when  the  Limbs  are 
not  much  feparated,  thereby  preventing  the  accefs  of  Air  to 
the  Internal  Parts,  which  they  at  the  fame  time  protect  and  con- 
ceal. 

The  upper  part  of  the  Pudendum,  named  Pubes  or  Mous  Ve- 
neris, is  fituated  on  the  fore-fide  of  the  Ofl'a  Pubis,  and  is  cover- 
ed with  Hair  fimilar  to  that  in  the  Male,  and  beginning  to  grow 
about  the  fame  period  of  life. 

The  Pubes  is  compofed  of  the  Common  Integuments,  under 
which  a confiderable  quantity  of  Fat  is  fituated,  rendering  it 
thick,  foft,  and  prominent. 

The  Labia  Pudendi  extend  from  the  Pubes  to  within  about  an 
inch  of  the  Anus,  the  fpace  between  the  Pudendum  and  Anus 
obtaining  the  name  of  Perineum,  from  a moifture  fuppofed  to 
flow  about  this  part  of  the  Skin. — It  is  fomerimes  alfo  called  An- 
terior Perineum,  to  diftinguifh  it  from  that  part  which  extends 
from  the  Anus  to  the  Coccyx,  termed  by  feme  Anatomifts  Po- 
Jlerior  Perineum. 

The  opening  between  the  two  Labia  has  the  name  of  PoJJ'a 
Magna  ; — it  increafes  a little  in  fize  and  depth  as  it  defeends,  and 
forms  a fmall  boat-like  Cavity  at  its  under  extremity,  termed 
FoJJ'a  Navicularis. 

The  Labia  are  thickeft  above,  become  thinner  below,  and  ter- 
minate in  a tranfverfe  fold  of  the  Skin,  named  Franum , Furcula , 
or  Fourcbette,  which  is  frequently  lacerated  in  the  fii ft  Child- 
birth. 

The  Labia  are  cotnpefed  of  the  Skin  elevated  by  a large  quan- 
tity of  Cellular  Subftance  and  fome  Fat,  and  lined  by  a very 
Vafcular  Membrane,  which  is  thin,  tender,  and  red  like  the  in- 
flde  of  the  Lips,  and  is  furnifhed  with  numerous  Sebaceous  Fol- 
licles, fecreting  a Liquor,  whereby  the  parts  are  preferved  frnooth 
and  moift. 

Between  the  upper  ends  of  the  Labia,  is  the  Subftance  named 
Clitoris,  and  by  fome  Mentula  Muliebris, — not  exceeding  an  inch 
in  length,  and  little  more  than  the  third  part  of  that  in  thicknefs, 
and  tied  down  to  the  fore-part  of  the  Symphyfis  Pubis. 


External  Parts. 


139 


It  is  extiemely  Vafcular  and  Nervous,  and  is  compofed,  like 
the  Penis  in  the  Male,  of  two  Crura  and  Corpora  Cavernofa, 
contained  in  a Ligamentous  Sheath,  with  a Septum  between 
them. 

The  Crura  are  upwards  of  twice  the  length  of  the  Body  of  the 
Clitoris,  and,  together  with  Mufcles  belonging  to  them,  arife,  as 
the  Crura  of  the  Penis  do  in  the  Male,  from  the  Crura  of  the  Offa 
Ifchia  and  Pubis. 

The  Clitoris  is  alfo  provided  with  a Ligamentum  Sufpenforium, 
by  which  it  is  conneCled  to  the  Ofla  Pubis,  and  with  a Gians , 
which,  like  that  of  the  Penis,  is  extremely  fenfible*  but  has  no 
perforation  in  it  for  the  paflage  of  the  Urine. 

It  is  covered  by  a continuation  of  the  Skin  of  the  Labia,  which 
at  its  inferior  extiemity,  forms  a Semilunar  Fold,  termed  Prepu- 
tiurn  Clitoridis. 

The  Prepuce  is  furnifhed  with  Glandula  Odorifera  upon  its 
inner  Surface,  and  with  a final!  Frsenum  which  fixes  it  to  the 
Gians. 

In  the  time  of  Coition,  the  Gians  Clitoridis  is  fuppofed  to  pro- 
duce nearly  the  fame  fenfation  in  the  Female,  as  the  Gians  Penis 
does  in  the  Male. 

At  the  under  and  outer  part  of  the  Clitoris  are  two  Bodies, 
called  Nymph re,  from  their  being  fuppofed  to  prefide  over  and  di- 
reCt  the  courfe  of  the  Water  proceeding  from  the  Bladder. 

The  Nympho:  arife  narrow  from  the  Prepuce  and  Gians,  and 
run  obliquely  downwards  and  outwards  along  the  infide  of  the 
Labia,  increafing  in  breadth,  but  fuddenly  contracting  again  at 
their  lower  extremity. 

They  are  chiefly  formed  by  a production  of  the  infide  of  the 
Labia,  have  the  fame  florid  colour  with  them,  and  in  their  natu- 
ral ftate  are  contiguous,  and  cover  the  Orifice  of  the  Urethra. 

They  are  fometimes  of  unequal  fize,  and  not  unfrequently, 
particularly  in  warm  climates,  they  projeCi  beyond  the  edges  of 
the  Labia. 

Their  Internal  Structure  coniifts  of  Cellular  Subllance,  with 
a large  proportion  of  Blood- veflels.  They  have  alfo  many  Ner- 
vous Papillae,  which  render  them  very  fenfible,  and  Sebaceous 
Follicles,  the  contents  of  which  prevent  them  from  being  injured 
by  the  Urine. 

The  Nymphse  aflift  in  directing  the  courfe  of  the  Urine  from 
the  Urethra,  and  in  preventing  the  Air  from  entering  the  Vagina. 
— They  alfo  tend  to  enlarge  thePaffage  for  the  Child  in  the  time 
of  Parturition. 

Between  the  Perineum  and  Nymphae,  there  is  afmooth  Cavity 
or  VeJUbulum,  which  is  molt  complete  in  Virgins,  and  leads  to 
two  Paflages,  viz.  to  the  Urethra  above,  and  to  the  Vagina  be- 
low. 


HO 


The  Orifice  of  the  Urethra  is  placed  a little  below  the  Gians 
of  the  Clitoris,  and  between  the  two  Nymphae,  and  is  furiound- 
ed  by  a Spongy  Eminence,  which  proje&s  at  its  under  part, — 
called  by  fome  Authors  Corpus  Glandulofum,  or  Glandule  P re- 
flate? Mulierum. 

The  Corpus  Glandulofum  is  perforated  by  Lacunee,  fome  of 
•which  are  of  conliderable  depth,  and  difeharge  a Vifcid  Matter 
round  the  Orifice  of  the  Urethra. 

The  Orifice  of  the  Vagina  termed  likewife  Os  Externum  Uteri, 
is  placed  immediately  under  that  of  the  Urethra,  and  is  natural- 
ly (traitef^Than  the  reft  of  the  Canal,  but  in  the  Virgin  (fate  is 
ftill  more  con  trafled  by  the  Subftance  called  Hymen,  or  C irculus 
Membranofus,  which  partly  furrounds  it. 

The  Hymen  approaches  to  a Circular  Figure,  but  the  Circle  is 
frequently  incomplete  next  the  orifice  of  the  Urethra,  the  broad 
part  being  turned  towards  the  Perineum. 

When  the  Hymen  is  ruptured,  it  degenerates  into  fmall  Coni- 
cal Papillse,  termed  Carunculte  Myrtiformes,  from  their  fuppofed 
refemblance  to  Myrtle  berries. 

The  Hymen  has  been  confidered  as  a Teft  of  Virginity  ; — 
but  neither  the  prefence  nor  abfence  of  this  Membrane  can  be 
depended  upon  as  a certain  Criterion. 

About  the  Orifice  of  the  Vagina  are  feveral  Mucous  Follicles, 
fimilar  to  thofe  round  the  Opening  of  the  Urethra. 

The  Blood-veffels  and  Nerves  of  the  External  Parts  are  from 
the  Pudic  Branches,  and  are  difperfed  in  numerous  Ramificati- 
ons upon  the  end  of  the  Vagina,  Labia  Externa,  and  Clitoris. 

The  Abfqrbents  pafs  partly  to  the  Inguinal  Glands,  and  partly 
to  thofe  placed  at  the  fides  of  the  Pelvis,  or  upon  the  Lumbar 
Vertebrae. 


.00000000-»00000000' 


OF  TIIE  GRAVID  UTERUS. 


When  the  Rudiments  of  the  Foetus  have  been  conveyed  from 
one  of  the  Ovaria  into  the  Cavity  of  the  Uterus,  through  the 
medium  of  the  correfponding  Uterine  Tube,  whether  in  the  ftate 
of  a Fluid  only,  or  of  a complete  Ovum,  Impregnation  is  faid  to 
have  taken  place. 


141 


Some  days  after  Impregnation  has  commenced,  an  Ovum,  con- 
fiding of  a Veficle  filled  with  a limpid  Fluid,  is  found  in  the  Ca- 
vity of  the  Uterus. 

The  Ovurn,  when  firft  vifible,  is  obferved  to  have  a fmooth 
Surface,  but  in  a (hort  time  thereafter  it  fends  off  flocculent 
Branches,  the  greater  part  of  which  are  by  degrees  converted  in- 
to a Placenta  at  that  part  of  the  Uterus  where  the  Ovum  happens 
to  be  firft  attached. 

The  Rudiments  of  the  Foetus,  however,  are  not  always 
conveyed  to  the  Uterus  after  Impregnation,  for  fometiines  a Foe- 
tus is  found  in  the  Ovarium  ; at  other  times  in  one  of  the  Uterine 
Tubes  j and  fome  rare  Inftances  have  occurred,  where  the  Em- 
bryo has  dropped  from  one  of  the  Ovaria  or  Tubes,  into  the  Ca- 
vity of  the  Abdomen,  where  a Placenta  has  been  formed,  by 
which  it  has  been  nouriftied. 

The  Ovum,  at  an  early  period  of  Geftation,  confifts  of  a thin 
Membranous  Capfule,  which  inclofes  the  Embryo  or  Germ  with 
the  Umbilical  Cord  and  Waters  ; and  the  Capfule,  again,  con- 
fifts of  an  internal  Membrane  called  Annios,  on  the  outfide  of 
which  is  the  ’True  Chorion,  which  is  covered  with  a Filamentous 
and  Spongy  Subftance,  termed  by  Ruysch  Tunica  Filamentofa, 
and  by  more  modern  Authors,  Falfe  or  Spongy  Chorion. 

The  Spongy  Chorion  is  defcribed  by  Dr.  Hunter  as  confid- 
ing, in  early  Geftation,  of  tnsjo  Layers,  one  lining  the  Cavity  of 
the  Uterus,  and  termed  by  him  Membrana  Decidua,  from  being 
fuppofed  to  be  call  off  from  the  Uterus  : The  other,  covering 
that  part  of  the  Ovum  which  does  not  adhere  to  the  Uterus,  he 
terms  Decidua  Reflex  a. 

The  Decidua  is  lead  diftimff  between  the  Uterus  and  Placenta. 
Near  the  edge  of  the  Placenta,  both  it  and  that  part  of  it  called 
Reflexa,  are  thickeftand  ftrongeft,  and  decreafe  in  thicknefs  tow- 
ards the  other  end  of  the  Uterus  and  Ovum,  in  proportion  as 
thefe  become  more  expanded. 

The  Decidua  and  Decidua  Reflexa  unite  into  one  Membrane 
in  advanced  Geftation.  They  have  been  fuppofed  to  be  formed 
originally  by  an  effloi efcence  thrown  out  upon  the  parts  on  v/hic^h 
they  are  placed,  in  the  manner  it  is  thrown  out  upon  inflamed 
l'urfaces. 

Between  the  Amnios  and  Chorion,  a Gelatinous  Fluid  is  con- 
tained in  the  early  Months,  at  which  period  a final  1 Bag,  filled 
with  a milky-l’ke  Fluid,  is  obferved  on  the  Amnios,  near  the 
Umbilical  Cord,  and  is  termed  Peflcnla  Umbilicalis  or  Alba. 

T'ne  Veficula  Umbilicalis  is  conceited  to  the  Cord  by  a Fila- 
ment confiding  of  an  artery  and  Vein;  which,  w'th  the  Fluid  and 
Bag,  foon  difappear.  The  life  of  this  Veficle,  which  has  fome- 
tiines been  miftaken  for  an  Allantois,  is  not  yet  ur.derftood. 

In  early  Geftation,  the  Ovum  is  large  in  proportion  to  the 
Embryo  ; but  towards  the  latter  period  of  Pregnancy,  the  propor- 
tion is  reverfed,  as  appears  from  the  following  Obfervations. 

■ . Sg|jfe; ft  -sMM.. j. 


142 


No  well  authenticated  account  has  been  yet  received,  of  the 
Embryo  being  obfervable  till  near  the  end  of  the  third  Week* 
when  it  is  found  to  appear  like  an  oblong  Veficle  floating  in  the 
limped  Liquor  of  the  Ovum. 

In  the  fourth  Week,  the  Ovum  is  about  the  fize  of  a Pigeon’s 
Egg,  and  the  Embryo  not  larger  than  that  of  a common  Fly. 

About  tire  end  of  the  third  Month,  the  Ovum  is  the  iize  of  a 
Goofe’s  Egg,  and  weighs  eight  ounces,  while  the  Embryo  is  be- 
tween two  and  three  ounces  in  weight,  and  three  inches  in  length  ; 
—and  the  Head  and  Extremities  being  now  diftincliy  obfervable, 
it  obtains  the  name  of  Faitus,  which  it  retains  from  this  time  till 
the  end  of  Geftation. 

In  the  fixth  Month  the  Placenta  and  Membranes  weigh  feven  or 
eight  ounces,  the  Foetus,  twelve  or  thiiteen,  and  is  tighter  nine 
Inches  in  length,  and  perfect  in  all  its  external  parts. 

At  Birth,  the  Seeundines  weigh  only  between  one  and  two 
pounds,  the  Foetus  lix  or  feven,  and  is  from  eighteen  to  twenty- 
two  inches  in  length. 

Still  however,  from  the  difficulty  of  ascertaining  when  Preg- 
nancy commences,— from  the  differences  of  Foetufesof  the  fame 
age  in  different  Women,  and  in  the  fame  Woman  in  different 
Pregnancies,  and — from  the  Foetus  being. -frequently  retained  in 
the  Uterus  fome  time  after  it  is  dead,  as  well  as  from  the  fmall 
dependance  to  be  placed  upon  many  of  the  Figures  given  of 
thefe  Parts, — the  above  Obfervations  are  not  altogether  to  be  de- 
pended upon. 

Changes  Produced  in  the  Uterine  System  by 


Immediate!  y after  Impregnaffon,  a large  Orifice  is  conftantly 
obferved  in  the  Ovarium,  leading  to  a Cavity  in  that  part  of  it 
from  whence  the  Rudiments  of  the  Foetus  have  been  derived. 

This  Cavity  appears  firft  floeculent,  and  is  afterwards  filled  up 
with  a Granulous  Subftance,  which  has  the  name  of  Corpus  Lu- 
teum, from  the  yellow  appearance  it  affumes,  efpecially  in 
Quadrupeds. 

The  Corpus  Luteum , confifts  of  an  outer  Vafcular,  and  an  in- 
ner Inorganic-looking  Subftance,  which  has  been  confidered  by 
fome  Authors  as  the  remains  of  the  Ovum. 

The  Corpus  Luteum  is  not  found  till  after  Impregnation.  It 
contines  during  Pregnancy,  and  for  fome  time  after  Delivery, 
when  it  gradually  vanifhes,  hut  leaves  a Scar  in  the  Ovarium, 
which  continues  for  life. — The  number  of  Corpora  Lutea  cor- 
refponds  with  that  of  the  Ova  impregnated. 

After  the  Embryo  is  received  into  the  Cavity  of  the  Uterus, 
the  Os  Tine*  is  (hut  up  by  a Ropy  Mucus  fecreted  from  the  Fol- 


Impregnation. 


143 


llcles  in  the  Cervix  Uteri  ; the  Menftrua  ceafe  to /«w, — and  the 
Uterus  by  degrees  is  changed  from  a triangular  to  an  oval  form. 

From  the  influx  of  Blood,  and  the  growth  of  the  Ovum,  the 
Cavity  of  the  Uterus  gradually  enlarges  from  a fize  capable  on- 
ly of  admitting  an  Almond,  to  that  which  contains  the  full- 
grown  Foetus,  the  Secundines  and  Waters  ; compofing  together 
a Mafs  equal  to  nine  or  ten  pounds  weight. 

Some  time  after  impregnation,  the  Fundus  and  Body  of  the 
Uterus,  being  fofter  and  loofer  than  the  Cervix,  firft  yield  to  the 
parts  which  it  contains. 

For  the  two  firft  Months,  the  Uterus  increafes  fo  little  as  to 
remain  in  the  Cavity  of  the  Pelvis,  and  it  is  generally  after  the 
third  month,  before  the  Tumour  formed  by  it  can  be  felt  above 
the  Symphyfis  of  the  Pubis. 

During  the  firft  three  Months,  the  Os  Tineas  remains  fmooth 
and  even,  and  its  Orifice  is  nearly  as  in  the  v,n--.ir.pregn;ited 
ftate ; but  between  the  third  and  fifth  Month,  the  Cervix  and 
Orifice  begin  to  be  dilated,  the  former  becoming  fofter,  and  the 
latter  changing  its  common  appearance,  and  projeiling  more  into 
the  Cavity  of  the  Vagina. 

The  Uterus  continues  to  rife  through  the  whole  period  of  Gef- 
talion,  but  frequently  inclines  a little- to  one  fide. — In  the  l’eventh 
Month,  it  reaches  the  Umbilicus,  and  at  laft  touches  the  Scro- 
biculus  Cordis,  Stomach  and  Colon,  occupying  rhe  whole  of 
the  Umbilical  Epigaftric  Regions. 

In  the  progrel's  of  Geftation,  the  whole  Uterus  becomes  fofter, 
loofer,  and  more  Vafcular,  and  the  Veflels  are  greatly  enlarged, 
the  proportional  increafe  being  nearly  fimilar  to  that  of  the  Ute- 
rus. 

The  courfe  of  the  Arteries  is  remarkably  convoluted, — fully 
as  much  fo  as  they  are  previous  to  Conception, — and  greatly  more 
fo  than  that  of  the  correfponding  Veins. 

The  Veins  are  much  larger  than  the  Arteries,  their  diameters 
being  fuch  as  to  have  diftinguifhed  thereby  the  name  of  Sinufes  j 
—and  to  them  the  great  bulk  of  the  Uterus  is  chiefly  owing. 

The  fubftance  of  the  Uterus  was  formerly  fuppofed  by  fome  to 
be  thicker,  and  by  others  to  be  thinner  in  the  Gravid,  than  in  the 
unimpregnated  ftate  ; but  the  generality  of  Anatomifts  feem  now 
fufficiently  fatisfied,  that  it  is  nearly  of  the  fame  thicknefs  in 
both  (fates,  and  during  t fie  whole  term  of  Pregnancy. 

In  the  latter  Monthsj  the  Tubercle  of  the  Os  Uteri  is  confi- 
derably  enlarged,  and  the  firmnefs  of  its  texture  converted  to 
tne  Spongy  foftnefs  of  the  Body  of  the  Uterus.  The  tranfverfe 
Rinia  or  Orifice  is  changed  into  an  oval  Pit,  and  in  Women  who 
have  borne  feveral  children,  it  is  confiderably  dilated  near  the  end 
of  Geftation. 

The  fituation  of  the  Appendages  of  the  Uterus  is  alfo  confide- 
rably altered.  The  Ovaria,  with  the  Tubes  and  Ligaments  of 


the  Uterus,  are  lower  fituated,  in  refpe£l  to  the  Fundus  Uteri, 
in  proportion  as  it  afcends  ; and  at  the  full  time,  the  Broad  Li- 
gaments, by  afliffing  in  forming  a covering  to  the  Uterus,  are 
nearly  obliterated. 

In  the  enlarged  (late  of  the  Uterus,  the  Mufcular  Fibres  are 
diftinctly  feen. — They  form  Fafciculi  which  run  in  various  di- 
rections, but  cannot  be  traced  far  without  interruption. 

A defcription  is  given  by  Ruysch  of  a Circular  Mufcle  in  the 
bottom  of  the  Uterus,  for  the  expulfion  of  the  Placenta  ; — but 
the  Placenta  is  found  to  adhere  to  other  parts  befides  the  Fundus 
Uteri;  nor  has  fuch  a Mufcle  been  obferved  by  later  Anato- 
mifts. 

The  Mufcular  Fibres  of  the  Uterus  aflift  in  the  delivery  of  the 
Child  and  expulfion  of  the  Placenta  ; and  in  a few  days  after- 
wards, the  Uterus,  partly  by  the  contraCtile  power  of  thefe  Fi- 
bres, and  partly  by  that  of  the  Blood-veffels,  is  reftored  to  near 
its  former  dimenfions. 

Contents  of  the  Uterus  about  the  end  of 
Pregnancy. 

The  Contents  of  the  Uterus,  towards  the  end  of  Pregnancy, 
con  lift  of  the  Foetus,  the  Umbilical  Cord  Placenta,  Membranes, 
and  Waters. 

The  Cord,  Placenta,  and  Membranes,  are  named  the  Secun- 
dines,  or  After-birth,  with  which  fome  include  the  Waters  though 
thefe  are  difcharged  previous  to  the  expulfion  of  the  Child. 

The  Cord  is  fixed  by  one  end  to  the  Umbilicus  of  the  Foetus, 
and  by  the  other  it  is  attached  to  the  Placenta  at  a little  diftanee 
from  its  middle,  from  which  circumftance  the  extra&ion  of  the 
Placenta  is  more  eafily  effeCled. 

It  is  commonly  about  two  feet  long, — in  fome  instances  moje, 
in  others  lefs  ; but  in  general  it  is  of  fufficient  length  to  allow  the 
Birth  of  the  Child,  while  the  Placenta  adheres  to  the  Uterus  of 
the  Mother. 

Its  thicknefs  is  nearly  equal  to  that  of  ones  Finger,  but  fmal- 
ler  and  weaker  at  the  extremity  next  the  Placenta. — It  is  feldom 
of  a cylindrical  form,  being  marked  with  Sulci  correfponding  to 
the  courfe  of  its  Veffels. 

It  is  compofed  of  one  Vein  and  two  Arteries,  which  twift  about 
each  other  in  a fpiral  direction,  and  are  covered  by  a fmooth  Coat 
derived  from  the  Membranes. 

The  Trunks  of  the  Veffels  are  inclofed  in  a Gelatinous  Cellular 
Subfance,  which  adds  to  the  (Length  and  elalficity  of  the  Cord, 
and  allows  the  Blood  to  pafs  freely  between  the  Foetus  and  Pla- 
centa, without  being  in  danger  of  interruption  from  preffure. 


145 


The  Vein  is  much  larger  than  the  Arteries  ; it  is  deftitute  of 
Valves,  and  fends  off  no  Branches  till  it  reaches  the  Foetus. 

It  arifes  from  the  fubftance  of  the  Placenta,  and,  after  perfo- 
rating the  Umbilicus,  it  paffes  in  the  inferior  part  of  the  Liga- 
mentum  Sufpenforium,  to  the  under  fide  of  the  Liver. 

The  Arteries  arifefrom  the  Iliac  Arteries  of  the  Foetus,  per- 
forate the  Umbilicus,  and  run  to  the  Placenta,  in  the  fubftance 
of  which  they  divide  into  their  ultimate  Branches,  vifriere  the 
Ramifications  of  one  Artery  frequently  form  large  Anaftomofes 
with  thofe  of  the  other,  and  both  communicate  with  the  Branches 
of  the  Vein,  in  the  manner  Arteries  and  Veins  do  in  other  parts 
of  the  Body. 

The  Ufe  of  the  Cord  is,  by  means  of  the  Vein,  to  convey  pure 
Blood  from  the  Placenta  for  the  nourilhment  of  the  Foetus,  and, 
through  the  medium  of  the  Arteries,  to  return  what  is  not  ufed 
in  Nutrition,  again  to  be  mixed  with  the  Blood  of  the  Uterus.— 
By  the  intervention  of  the  Cord  alfo,  the  Placenta  is  more  readi- 
ly extrafled. 

The  Placenta  fo  called  from  its  refemblance  to  a broad  Cake, 
is  a fpongy  mafs,  of  a round  form,  occupying  near  a fourth  part 
of  the  Ovum. 

It  is  about  feven  or  eight  inches  in  breadth,  and  upwards  of 
one  inch  in  thicknefs,  but  is  thinner  at  the  edges  where  the  Mem- 
branes go  off. 

The  external  futface,  or  that  next  the  Uterus,  is  divided  into 
Lobules  with  deep  FifTures,  while  the  internal,  or  that  next  the 
Foetus,  forms  a regular  Mafs,  which  has  numerous  large  Branch- 
es of  the  Umbilical  Veffels  difperfed  upon  it. 

In  the  Placenta  are  to  be  oblerved, — on  the  fide  next  the  Child, 
the  ramifications  of  the  Umbilical  Veffels  forming  the  principal 
part  of  its  fubftance, — on  the  fide  next  the  Mother,  Branches  of 
the  Uterine  Arteries,  almoft  of  the  fize  of  Crow-quills,  palfin^ 
in  a convoluted  manner  between  the  U Writs  and  Placenta,  and 
terminating  in  the  latter  ; — Veins  correlponding  with  thefe  Ar- 
teries but  flat  and  of  great  fize,  running  obliquely  to  the  Ute- 
rus,— and,  in  the  fubftance  of  the  Placenta,  an  Appearance 
which  has  been  fuppofed  by  many  Authors  to  be  the  common 
Cellular  Membrane,  of  a tender  nature,  and  eafily  ruptured  by 
injection,  but  which  is  confidered  by  late  Authors  as  a regular 
Spongy  Subftance,  fimilar  to  that  in  the  Body  of  the  Penisf 

The  Placenta  is  connefted  to  the  Uterus  on  one  fide,  by  Blood- 
veffels  and  by  the  Decidua,  and  to  the  Foetus  on  the  other  bv 
means  of  the  Umbilical  Cord.  ’ i 

The  common  place  of  attachment  is  near  the  Fundus  Uteri 
though  it  is  found  at  different  times  adhering  to  all  the  other  parts 
of  the  Uterus,  not  even  the  Os  Tincse  excepted.  ^ 

In  the  cafe  of  Twins,  there  is  fometimes  only  one,  but  raoft 
frequently  two  diltindl  Placentae,  adhering  together  br  the  in- 
VOL.  II.  N 


146 


tervention  of  a Membrane  in  which  the  Veflels  of  the  two  Pla- 
centa: occafionally  communicate  with  each  other. 

There  are  in  thefe  cafes  alfo,  two  diftinff  Apartments  feparated 
by  a Partition,  each  Apartment  containing  its  own  Waters  and 
Cord. 

The  Ufe  of  the  Placenta  is,  to  receive  Blood  from  the  Uterus, 
and,  according  to  the  opinion  of  modern  Anatomifts,  to  purify 
it,  (as  the  Lungs  do  in  the  Adult),  for  the  nourifliment  of  the 
Foetus. 

The  Membranes  confift  of  the  Spongy  Chorion,  the  True  Chorion , 
and  the  Amnios. 

They  form  a complete  but  (lender  Bag,  which  lines  the  Ca- 
vity of  the  Uterus,  and  inclofes  the  Foetus,  Umbilical  Cord,  and 
Waters. 

The  Spongy  Chorion  is  a thick  opaque  fubftance,  which  adheres 
to  the  Uterus,  and  forms  the  outer  Layer  of  the  Ovum,  but  fcarce- 
Jy  penetrates  between  the  Lobules  of  the  Placenta. 

Between  the  Uterus  and  Placenta,  it  is  lefs  d i ft i n 61  than  elfe- 
where,  being  perforated  there,  and  in  fome  degree  concealed  by 
the  Blood -veflels  proceeding  from  the  inhdeof  the  Uterus. 

It  has  a Spongy  and  Villous  appearance,  and  is  full  of  fmall 
Blood-vefl'els,.  which  can  be  readily  injefted  from  thofe  of  the 
Uterus. 

The  True  Chorion, — the  term  derived  from  Chorus'p  Company, 
numerous  Veflels  being  found  to  exifl:  in  it  in  the  Qua'fruped,-— 
is  thinner,  fmoother,  and  much  denfer  than  the  former. 

It  is  connected  with  the  Spongy  Chorion  as  far  as  the  edge  of 
the  Placenta,  where  it  fepai  ates  from  it,  is  reflefted  over  the  Sur- 
face of  the  PI  '.centa,  which  is  oppofed  to  the  Foetus,  and  is  af- 
terwards continued  over  the  whole  of  the  Cord. 

It  is  uniform  in  its  texture,  has  a tranfparent  appearance,  ad- 
heres to  the  Spongy  Chorion  and  furface  of  the  Placenta,  by  a de- 
licate Cellular  Subftance,  and  has  no  Veflels  vifible  to  the  naked 
Lye,  or  which  can  be  in*e<Sted. 

The  Amnios , — fo  called,  according  to  fome  Authors,  from  its 
fuppofed  ; efemblance  to  a Veflel  ufed  by  the  Ancients  for  the  re- 
ception of  Blood  in  Sacrifice, — lines  the  Surface  of  the  True  Cho- 
rion, and,  with  it,  is  refle&ed  from  the  Placenta  upon  the  Cord, 
which  it  fupplies  with  an  external  covering. 

It  is  thinner,  more  denfc,  and  tranfparent,  than  the  Chorion, 
to  which  it  adheres  every  where  by  a Jeliy. 

It  is  fmooth  and  polifhed  on  the  fide  next  the  Foetus,  and  is 
■deftitute  of  Blood- veflels. 

The  Membranes,  bei’des  containing  the  Child  and  Waters, 
give  origin  to  the  latter,  and,  in  the  time  of  Labour,  aflift  in  open- 
ing the  Orifice  of  the  Uterus. 

"The  Waters,  called  Liqour  Amnii,  are  thinned:  and  cleared  in 
the  fir  ft  Months,  after  which  they  acquire  fome  degree  of  colour 
and  ropinefs. 


147 


The  Liquor  Amnii  is  chiefly  compofed  of  the  Serum  of  the 
Blood.  In  its  natural  Hate,  it  has  all  the  Charafters  of  the  Li- 
quor Pericardii,  or  of  the  Liquors  exhaled  from  the  Surfaces  of 
other  Membranes  fimilar  to  the  Pericardium. — It  is  fuppofed  to 
be  d erived  from  the  Exhalent  Arteries  of  the  Amnios. 

It  is  proportionally  greater  in  quantity  in  the  firft  than  in  the 
laft  Months,  but  the  proportion  and  quantity'  vary  confiderably 
in  different  Women,  and  in  the  fame  Woman  in  different  Preg- 
nancies. 

Between  the  Amnios  and  Chorion,  Water  is  frequently  coi- 
le£led,  but  in  much  fmaller  quantity  than  in  the  Amnios,  and  is 
termed  Falfe  Water,  or  Falfe  Deli-very. — It  is  frequently  ail- 
charged  forae  time  previous  to  the  Birth  of  the  Child,  without  any 
danger. 

The  Liquor  Amnii  defends  the  Child  and  Umbilical  Veffels 
from  the  preffure.of  the  Uterus,  afliits  in  di {lending  the  Uterus 
duiing  Geffation,  and  allows  the  Foetus  a certain  degree  of  mo- 
tion. 

In  the  time  of  Labour,  it  alfb  aflifts  iu  dilating  the  Mouth  of 
the  Uterus,  and,  by  lubricating  the  Vagina,  facilitates  Delivery . 

Peculiarities  of  the  Fcetus. 

All  the  Bones  of  the  Body,  excepting  a few,  are  fojt, yield- 
ing, and  imperfect , and  many  of  them  entirely  in  a fate  of  Car- 
tilage. . 

File  Head  is  large  in  proportion  to  the  reft  of  the  Body,  and  the 
Bones  of  the  Cranium  are  united  by  Membrane,  which  allows  the 
nze  of  the  Head  to  be  diminiflied,  whereby  its  Paffage  is  facilita- 
ted in  the  time  of  Delivery. 

Between  the  Frontal  and  Parietal  Bones,  is  the  Membrane 
called  Bregma,  formed  by  the  Dura  Mater  and  Pericranium, 
which  commonly  difappears  before  the  Child  is  two  years  of  age, 
the  margins  of  the  Bones  being  then  united, 

—The  other  peculiarities  of  the  Bones  o f the  Foetus  are  taker,  no- 
tice of  in  the  Defer  iftion  of  the  Bones  of  the  Adult. — 

There  is  a large  proportion  of  Fluids,  and  the  Solids  are  gene- 
rally /o//er  than  in  the  Adult. 

The  Skin  is  of  a bright  red  colour,  in  confequence  of  its  greater 
degree  of  Vafcularity. 

That  part  chiefly  of  the  Cellular  Membrane  is  Adijnfe,  which 
is  upon  the  Surface  of  the  Body  ; fcarcely  any  Fat  being  found 
in  the  interior  parts,  where  it  gradually  accumulates  as  the  per- 
fon  grows  older. 

The  Brain,  Spinal  Marrov/,  and  Nervous  Syftem,  are  propor- 
tionally larger,  but  fofter. 

The  Sanguiferous  Syftem,  and  Glandular  Organs,  are  larger. 

In  the  Eye  is  the  Metnbrana  Pupillaris,  which  arifes  from  the 
nner  margin  of  the  Iris,  and  completely  covers  the  Pupil. 


143 


It  leparates  the  Camerae  from  each  other,  and  is  very  Vafcular, 
According  to  Blumenbach,  itkeeps  the  Iris  expanded, during 
the  rapid  increafe  of  the  Ball  of  the  Eye. 

The  Cryftalline  Lens  is  almoft  Spherical,  and  has  numerous 
yeJJ'els  difperied  upon  its  Caplule. 

The  Meatus  Auditorius  is  wholly  Cartilaginous,  and  adheres 
by  its  extremity  to  an  impeifefl  Bony  Circle,  in  which  the  Mem 
brana  Tympani  is  placed. 

The  Meatus  Extei  nus,  and  Membrnna  Tympani,  are  lined  by 
a Mucous  Membrane,  which  is  call  off  after  Birth. 

The  Thymus  Gland,  in  the  Foetus,  is  a large  Subftauce,  fitu- 
ated  in  the  upper  part  of  the  Thorax,  between  the  Layers  of  the 
Anterior  Mediaftinum. 

It  lies  over  the  Pericardium,  and  occupies  the  fpace  where  the 
Aorta  fends  off  the  Carotid  and  Subclavian  Blanches,  and  ex- 
tends a fhort  way  into  the  fore-part  of  the  Neck. 

It  has  tvuo  long  Cornua  above,  and  t-zuo  broad  Lobes  below, 
is  of  a pale-red  colour,  and  becomes  afterwards  of  a darker  hue. 

A nvhile  ferous  liquor  can  frequently  be  fqueezed  from  its  fub- 
flance  ; but  it  has  no  Excretory  Duff  ; nor  is  the  ufe  of  the  Fluid, 
or  of  the  Gland  itfelf,  yet  afeertained. 

Some  Anatomifts  are  of  opinion,  that  the  white  Fluid  is  Chyle 
fent  by  a retrogade  motion  from  the  Thoracic  Du£l,  and  that  the 
Thymus  Gland  is  a Diverticulum  to  the  Chyle,  when  too  great 
a quantity  of  Lymph  is  fent  to  the  Subclavian  Vein. 

In  the  Adult,  the  Thymus  Gland  is  fo  completely  abfoi  bed, 
that  fcarcely  any  thing  but  Cellular  Subftance  remains  in  its 
place. 

The  Blood-veffels  of  the  Thymus  are  Branches  of  the  Sub- 
clavian and  Internal  Mammary  ; the  Nerves  come  from  the  Great 
Sympathetics  and  Eighth  Pair. 

Its  Lymphatics  have  not  yet  been  very  accurately  traced. 

The  Lungs  are  fmall,  firm,  and  of  a dark-red  Colour,  and  Jink 
when  thrown  into  water,  in  confequence  of  the  Bronchial  Cells 
having  not  yet  received  A:r. 

But  if  Air  be  admitted  to  them  by  putrefaffion  or  otherwife, 
they  fiwim  in  Water,  in  the  fame  manner  as  if  Air  had  been  cen- 
veyed  to  them  in  confequence  of  Refpiration. 

The  Valve  of  Euftachius  is  difnnSl  in  the  Fcetus,  but  frequent- 
ly Cribriform  in  the  Adult,  is  larger  in  proportion,  and  is  fup- 
pofed  to  direft  the  Blood  of  th^  Inferior  Cava,  immediately 
through  the  Foramen  Ovale  to  tiucLeft  Auricle. 

In  the  back-part  of  the  Septufn,  between  the  Right  and  Left 
Auricles,  is  the  Foramen  Ovale,  nearly  equal  in  fize  to  the 
Mouth  of  the  Inferior  Cava,  bounded  by  a thick  Mufcular  edge, 
termed  Annulus  Foraminis  Ovalis. 

Upon  the  left  fide  of  the  Foramen  Ovale,  a Membranous  Valve 
is  placed,  which  allows  part  of  the  Blood  of  the  Right  Auricle 


149 


to  pafs  through  the  Foramen  Ovale  immediately  to  the  left  one, 
but  which  completely  prevents  its  return. 

The  Blood  going  through  the  Foramen  Ovale,  afbfts  in  keep- 
ing up  the  balance  of  Circulation  between  the  two  fides  ot  the 
Heart,  till  the  Lungs  be  ready  to  receive  it. 

ThePulmonary  Artery  divides  into  three  Branches,  the  right 
and  left  of  which  run  to  the  Lungs,  while  the  middle  one,  called 
Dufius  Arteriofus , larger  than  both  the  other  Branches,  and  its 
Area  nearly  equal  to  that  of  the  Foramen  Ovale,  pafles  in  an  ob- 
lique direction  to  the  beginning  of  the  defcending  Aorta. 

The  Dufius,  or  Canalis  Arteriofus,  forms  nearly  one  half  of 
the  Aorta,  carries  part  of  the  Blood  of  the  Right  Ventricle  into 
that  Artery,  without  allowing  it  to  pafs  to  the  Lungs  ; and  the 
Aorta,  formed  in  this  manner,  receives  thefo  ce  of  both  Ventri- 
cles, by  which  it  is  more  enabled  to  fend  Blood  through  the  Um- 
bilical Arteries  to  the  Placenta. 

The  Stomach  is  of  a rounder  form  than  in  the  Adult,  and  com- 
monly contains  a fmall  quantity  of  a Gelatinous  Matter. 

The  Appendix  Vermiformis  is  larger  in  proportion,  and  is  in- 
ftrted  into  the  extremity  ©f  the  Colon,  which-,  at  this  time,  does 
not  projefl  to  foim  a. proper  Cxcum. 

The  Colon,  and  fiequently  all'o  the  end  of  the  Ilium,  are 
filled  with  a greenijh  black  Faces,  of  a vifcid  coqiiftence,  termed 
Miconium . 

The  Liver  is  fo  large  as  to  occupy  both  Hypochondriac  Re- 
gions. 

The  Umbilical  Fein  pafles  from  the  Umbilicus,  in  a duplicature 
ot  the  Peritoneum,  to  the  left  Branch  of  the  Vena  Portae,  and 
carries  the  Blood  from  the  Placenta  to  the  Liver. 

From  the  Trunk  of  the  Umbilical  Vein,  where  it  terminates  in 
the  Liver,  a Branch,  called  DuFlus,  or  Canalis  Venofus,  runs  in  a 
iomewbat  waving  direflion,  and  joins  the  Left  Vena  Hepatica, 
where  that  Vein  enters  the  Cava. 

The  Dufius  Venofus  is  much  fmaller  than  the  Trunk  of  the 
Umbilical  Vein,  and  carries  part  of  the  Blood  of  the  Vein  direfl- 
ly  to  the  Heart,  without  allowing  it  to  enter  the  Circulation  in 
the  Liver. 

The  Umbilical  Vein  fends  Branches  to  the  Right  Lobe  of  tli« 
Liver,  but  is  principally  diftributed  through  the  Left  Lobe; 
while  the  Right  Branch  of  the  Vena  Ponte  carries  the  Blood 
of  the  Splenic  and  Mel'enteric  Arteries  to  the  Right  Lobe  of  the 
Liver. 

After  Birth,  the  Left  Lobe  of  the  Liver,  which  was  formerly 
more  particularly  fupplied  by  the  Umbilical  Vein,  receives  an  ad- 
ditional proportion  of  Blood  from  the  Vena  Portarum. 

The  reafon  why  the  Umbilical  Vein  goes  partly  to  the  Cava, 
and  not  entirely  to  the  Heart,  is  not  underftood. 

Vol.  II.  In  2 


150 


The  Kidneys  are  irregular  on  their  Suiface,  being  formed  of 
Lobes,  each  of  which  confilts  of  a Cortical,  a Medullary  part,  and 
a Papilla,  and  is  covered  by  a Proper  Membrane. 

1 he  Giandula  Renalis  is  almolt  as  large  as  the  Kidney,  but  af- 
terwards rather  diminifhes  than  increafes  in  fize. 

The  Bladder  of  Urine  is  of  a long  form,  and  extends  almoft 
to  the  Umbilicus.  The  greater  part  of  it  is  above  the  Pelvis,  and  is 
more  particularly  covered  by  the  Peritoneum  than  in  the  Adult. 

1 he  Urachus,  which  is  of  a Conical  form,  alcends  from  the 
bottom  of  the  Bladder,  between  the  Umbilical  Arteries,  and  be- 
tween the  Peritoneum  and  Linea  Alba,  to  the  Umbilicus,  and 
vaniihes  by  degrees  in  the  Umbilical  Cord. 

It  is  formed  by  a production  of  the  Fundus  Veficae,  and  in 
the  Human  Body  is  generally  folid,  forming  a Sufpenfory  Liga- 
ment of  the  Bladder. 

It  has  been  fometimes  found  hollow  at  its  beginning  and 
has  been  laid  to  be  fo,  in  one  or  two  inftances,  throughout  its 
whole  length. 

In  the  Foetal  Quadruped,  it  is  a large  Tube,  which  tranfmits 
Urine  from  the  Bladder  to  a Bag  between  the  Amnios  and 
Choi  ion,  called  Allantois. 

The  common  Iliac  Arteries  divide,  on  each  fide,  into  a fmall 
External,  and  large  Internal  Branch. 

The  principal  part  of  the  Internal  Iliac  is  occupied  in  forming 
the  Umbilical  Arteries,  which  mount  by  the  (ides  of  the  Bladder, 
on  the  outfide  of  the  Peritoneum,  and  perforate  the  Umbilicus 
in  their  progrefs  to  the  Umbilical  Cord. 

Soon  after  Delivery,  the  Foramen  Ovale,  Dutus  Arteriofus, 
and  Venofus,  with  the  Umbilical  Vein  and  Arteries,  begin  to 
contrail,  and  are,  in  general,  completely  clofed,  and  the  Veflels 
fhri veiled  into  Ligaments  within  a year  after  Birth. 

This  obliteration  is  produced  by  a contractile  power  in  the  parts, 
by  a preflure  in  the  l'urrounding  Vifcera,  and  by  the  Blood  being 
direted  through  other  channels. 

The  Pelvis  of  the  Fcetus  is  commonly  fo  fmall,  that  the  prin- 
cipal parts  of  its  Vifcera  are  contained  in  the  open  cavity  of  the 
Abdomen. 

The  Prepuce  of  the  Clitoris  is  proportionally  fo  much  larger  in 
a young  Fcetus  than  it  is  afterwards,  that,  in  an  Abortion,  a Fe- 
male Foetus  has  been  frequently  miflaken  for  a Male. 

The  Teltes  are  lodged  during  the  greater  pa;  t of  Geftation,  in 
the  Cavity  of  the  Abdomen,  over  the  Pfoas  Mufcles,  and  a lit- 
tle below  the  Kidneys. 

They  then  conflitutea  part  of  the  Abdominal  Vifcera,  and,  in 
a fimilar  manner  with  them,  are  connected  to  the  Body  by  a pro- 
duction of  the  Peritoneum,  which  forms  their  Tunica  Albu- 
ginea. 


151 


Between  the  Tefticle  and  Scrotum,  a Fibrous  and  Vafcular 
Subftance,  of  a conical  form,  is  extended, — called  by  Mr. 
Hunter,  Gubernaculum,  or  Ligamentum  Tejris,  which  he  con - 
fiders  as  a principal  agent  in  directing  the  courle  of  the  Tefticle, 
and  in  making  way  for  it  in  its  defcent. 

About  the  eighth  month  of  Pregnancy,  the  Teftis,  by  means 
not  yet  completely  afcertained,  pafles  gradually  along  to  the 
Scrotum,  a Procefs  of  the  Peritoneum  preceding  it,  which  af- 
terwards forms  its  Vaginal  Coat. 

The  Teltis  through  the  whole  of  its  courfe,  continues  to  be 
cohered  by  the  Peritoneum,  is  connected  to  the  parts  on  which  it 
reds,  and  has  its  Vefiels  palling  to  it  from  behind  forwards,  the 
fame  as  when  fituated  in  the  Abdomen. 

While  the  tefticle  is  palling  through  the  Ring  of  the  Abdomi- 
nal Mufcle,  the  Ligamentum  Teftis  is  found  to  be  in  fome  mea- 
i'ure  inverted,  and  to  form  the  under  and  fore-part  of  the  Vaginal 
Coat,  on  which  the  Cremafter  Mufcle  is  expanded. 

After  the  defcent  of  the  Tefticle,  the  Peritoneal  Procefs,  which 
defcends  along  with  it,  begins  to  contrail  at  the  Ring,  and  a firm 
adhefion  of  its  fides,  to  within  a little  diftance  of  the  Tefticle, 
is  commonly  found  to  he  produced  by  the  time  of  Birth. 


In  the  firft  Months,  the  Embryo  fwims  in  the  L’quor  Amnii, 
free  from  the  prelfure  of  the  furrounding  parts  and  from  many 
diffisitions  and  obfervations  made  by  the  lateft  Anatomifts,  it  is 
afcertained, — that  the  Head  preponderates,  and  in  general  con- 
tinues undermoft  till  the  Child  is  delivered. 

Formerly  it  was  fappofed  that  the  Embryo,  in  the  firft  Months, 
was  fituated  with  the  Head  uppermoft,  and  that,  in  the  latter 
Months,  the  attitude  of  the  Foetus  was  inverted. 

The  Foetus  is  obferved  to  be  coiled  up  into  as  round  a figure 
as  polfible,  fo  as  to  be  properly  adapted  to  the  Cavity  of  the 
Uterus. 

The  Head  is  bent  towards  the  Thorax,  and  the  arms  are  folded  : 
— The  Knees  are  drawn  towards  the  Abdomen,  and  the  Heels 
towards  the  Nates. 

The  Spine  s bent  into  an  Arch,  and  one  fide  of  the  B .dy  of 
the  Foetus  i : frequently  turned  forwards. 

The  Head  is  placed  diagonally,  with  its  long  Diameter  corre- 
fponding  to  that  of  the  Pelvis,  and  the  Occiput  oppofed  to  the 
Os  Tincae. 

Circulation  of  the  Blood  in  the  FoeTUs. 

The  Blood  is  ftnt  by  the  ArteAesof  theUteius  to  the  Sub- 
ftance of  the  Placenta,  from  which  accord  ng  to  moft  of  the 
ancient  An.it  ,-  fts,  p aflr.s  to  the  Umhibcal  Vein  by  a di- 
refl  -.om.v.u  .in  of  B'fnches;  or,  acco  ding  to  the  opinion 
of  the  greate  . n or  modern  Anatomifts, — by  Abforbtion. 


Position  of  the  Fostus. 


152 


' By  the  Umbilical  Vein  it  goes  principally  to  be  circulated  in 
the  Liver,  and  by  the  Du£lus  Venofus,  a fmall  portion  of  it 
goes  to  the  right  Auricle  of  the  Heart. 

The  Blood  fent  from  the  Inferior  Cava  is  tranfmitted  by  the 
Foramen  Ovale  to  the  left  Auricle,  and  that  fent  by  the  Superior 
Cava  is  tranfmitted  to  the  right  Auricle  and  Ventricle,  and  from 
thence  to  the  Pulmonary  Artery. 

From  the  Pulmonary  Artery,  one  portion  of  it  paffes  through 
the  Circulation  of  the  Lungs,  and  another  goes  by  the  Duc- 
tus Arteriofus  to  the  Aoita  Defcendens. 

From  the  Lungs  it  is  returned  by  the  Pulmonary  Veins  to  the 
Left  Auricle,  where  it  mixes  with  that  coming  from  the  right 
Auricle  by  the  Foramen  Ovale,  and  is  fent  by  the  Aorta  to  the 
different  parts  of  the  Body. 

From  the  Iliac  Arteries,  it  is  conveyed  by  the  Umbilical 
Branches  to  the  Subftance  of  the  Placenta,  where  one  portion  of 
it  returns  by  correfponding  Veins  to  the  Foetus,  the  reft  going 
to  the  Uterus  in  the  manner  it  was  difeharged  from  the  Uterine 
Arteries  to  the  Branches  of  the  Umbilical  Vein. 


1.53 


PART  V. 


OF  THE 


ABSORBENT  STSTEM. 


Of  the  Absorbents  in  General. 


THE  Abforbent  Syflem  confifts  of  the  Ahforhent  Veffels  and 
Conglobate  Glands,  the  former  of  which  are  divided  into  Lym- 
phatic and  Lafteal  Vefj'els. 

The  Abforbents  are  fmall  pellucid  Tubes,  which  have  been  dif- 
covered  in  moll  parts  of  the  Body,  and  are  fuppofed  to  exift  in 
all. 

They  begin  by  numberlefs  open  Mouths,  too  minute  to  be  via- 
ble to  the  naked  Eye;  though,  by  the  afTiftance  of  Glades,  the 
Orilices  of  the  La£Ieals  have  been  feen  in  the  Human  Body  by 
Mr,  Cruickshank,  and  thole  of  the  Lymphatics,  in  certain 
k nds  of  Fillies,  by  Dr.  Monro. — See  their  Treatifes  upon  ibis 
Subjell. 

They  arife  from  the  external  Surface  of  the  Body,  from  the 
Cellular  Subrtance,  from  the  Surfaces  of  the  large  Cavities,  and 
from  the  Surface  and  Subfiance  of  the  different  Vil'cera; — but 
have  not  yet  been  obferved  in  the  Cavity  of  the  Cranium,  or  in 
the  Placenta  and  its  Membranes. 

In  the  dfferent  parts  of  the  body  in  general  they  run  in  two 
fets,  one  fuperficial  and  very  numerous,  the  ether  accompanying 
the  Arteries,  and  at  leaft  double  their  number. 

The  Lafteals  are  of  the  lame  nature  with  the  other  Abforbents. 
They  begin  from  the  infide  of  the  Intertines,  and,  when  thel’e 
conain  Alimentary  matter,  they  carry  a white  Fiuid,  called 
Chyle,  and  at  other  time;,  a Clear  Fluid  or  Lymph,  to  be  mixed  with 
the  contents  of  the  Lymphatics, 


15-4 


Moft  of  the  Lymphatics,  and  all  the  La&eals,  terminate  in 
the  Thoracic  Duff,  by  which  the  Lymph  and  Chyle  are  conveyed 
to  the  Red  Veins,  to  be  mixed  with  the  Blood. 

The  common  place  of  termination  is  in  the  large  Veins  in  the 
bottom  of  the  Neck  ; — no  Fadls  or  obfervations  having  been  yet 
eftablifhed  of  their  terminating  in  any  other  part  of  the  Venous 
Syftem. 

The  Coats  of  the  Abforbents  are  thinner  and  more  tranfparent, 
but  ftronger  than  thofe  of  the  Red  Veins,  being  able  to  fupport 
a Column  of  Mercury  of  confiderable  weight ; but  from  their 
thinnefs  they  cannot  be  enumerated. 

They  are  generally  fuppofed  however  to  be  formed  of  different 
Membranous  Layers,  like  the  Blood-veffels.  Fibres  can  be  feen 
in  them,  and  their  Mufculaiity  is  rendered  probable  by  the  Con- 
traftile  power  which  they  are  obferved  to  poflefs  in  a living  or 
moribund  Animal. 

By  this  conti ability  they  convey  their  contents  from  their  Ori- 
gins towards  their  terminations,  in  which  they  areaflifted  by  the 
motions  of  the  1'urrounding  parts,  independent  of  fuch  a Vis  a 
tergo  as  contributes  to  propel  the  Blood  through  the  Veins. 

They  are  furnifhed  with  Blood-vejfels  for  their  nourifhment,  as 
is  fcmetimes  obferved  by  penetrating  injections  ; and  this  is  ren- 
dered (fill,  more  evident  by  their  being  fufceptible  of  inflamma- 
tion and  pain. 

Theprefence  of  Ner-ves., alfo  appears  probable  from  the  acute- 
nefs  of  their  feeling  when  in  a (fate  of  inflammation. 

In  general,  they  form  an  irregular  Net-work,  having  frequent 
communications  with  each  other ; and  thefe  are  moft- numerous 
in  the  vicinity  of  their  Glands. 

Through  their  whole  extent,  they  are  intercepted  by  Valves, 
which  are  placed  in  pairs,  and  are  of  a femicircular  form,  having 
one  edge  of  each  Valve  fixed  to  the  fide  of  the  Vefl'el,  and  the 
other  edge  loofe  acrofs  its  cavity,  but  turned  towards  the  general 
terminations. 

The  Valves  are  found,  in  fome  parts,  to  be  fituated  at  equal 
diftances  ; in  others,  more  irregularly. — Their  number  alio  is 
very  uncertain,  amounting  in  fome  parts  to  three  or  four,  and 
in  others  to  feven  or  eight,  or  upwards,  in  the  length  of  an  inch  ; 
— but  varying  ftill  more  with  refpeCl  to  number,  in  different 
Bodies,  and  in  different  parts  of  the  fame  Body. 

When  the  Abforbents  are  diftended,  they  appear  largeft  on  the 
fide  of  the  Valves  towards  their  general  termination,  and  the  en- 
largements are  fuch  as  to  give  the  Lymphatics  a jointed,  and  the 
Lafteais  frequently  a veficular  appearance. 

In  the  termination  of  the  Abforbents,  whether  in  the  Thora- 
cic DuCt,  or  in  the  Red  Veins,  there  is  always  one  and  common- 
ly two  Valves,  to  prevent  the  contents  of  the  Du£t  or  of  the 
Veins  from  palling  into  them. 


155 


The  Ufe  of  the  Valves  is  to  promote  the  general  courfe  ol  the 
Lymph  and  Chyle,  and  to  prevent  the  retrograde  motion  of  thefe 
Fluids  within  their  VefTels. 

Ufe  of  the  Abforbents  : The  Lymphatics  take  in  the  Fluids  ap- 
plied to  their  Orifices  by  Capillary  A'  traftion,  and  by  a power 
inherent  in  themfelves,  and  by  their  contrailile  nature  condufl 
them  into  the  Mafs  of  Blood,  whereby  they  pievent  morbid  ac- 
cumulations.— The  LaHeals,  in  like  manner,  receive  the  Chyle 
from  the  Inteftines  for  the  nourifhment  of  the  Boay. 

The  Conglobate  Glands,  or  Glar.ds  of  the  Abforbent  VefTels, 
are  found  in  various  parts  of  the  Body,  and  are  fi  tutted  in  the 
Cellular  Subftance  under  the  Skin,  or  over  the  Trunks  of  the 
Blood-veffels  belonging  to  the  different  Vifcera  They  are  of  a 
round  or  oval  form,  and  frequently  a little  flattened. 

They  are  of  different  fizes,  from  that  of  a Millet-feed  to  that 
of  a Subftance  near  an  inch  in  diameter  ; and  fometimes  feveral 
are  collefted  into  one  mafs. 

Their  colour  alfo  varies  in  different  parts  of  the  Body,  and  at 
different  times  of  life. 

In  young  fubjefts,  they  are  generally  Iargeft,  and  of  a reddifh 
or  brown  colour,  but  become  fmaller  and  paler  with  increafing 
age;  and  immediately  under  the  Skin,  they  are  redder  and  firmer 
than  within  the  large  Cavities. 

They  have  a fmooth,  denfe,  Membranous  Covering,  which 
gives  them  a fhining  appearance,  and  are  conneffted  to  the  fur- 
rounding parts  by  loofe  Cellular  Subftance. 

Their  Coat  is  connected  to  the  Glandular  part  by  a Cellular 
Membrane,  which,  according  to  Dr.  Haller,  is  pervaded  by 
a Succus  proprius  full  of  Globules,  which,  Mr.  HEWSON  fup- 
pofed,  afterwards  form  the  Red  Globules  of  the  Blood. 

L:ke  other  Glands,  they  have  Arteries,  Veins,  and  Nerves, 
entering  their  compofition. 

They  are  deferibed  by  fome  Anatomifts,  as  being  compofed  of 
Cells  internally , while  others  confider  them  as  being  a Congeries 
of  convoluted  Abforbent  VefTels. — Moil  of  the  Glands  have  much 
of  the  former,  but  many  of  them  of  the  latter  appearance. 

; The  Abforbents  entering  into  the  Glands,  are  called  Vafa  In- 
ferentia.  When  they  approach,  or  come  in  contact  with  the  Gland, 
they  fplit  into  radiated  Branches,  which,  after  fpreading  over  it, 
penetrate  into  its  Subftance. 

The  greater  part  of  the  Abforbents,  approaching  a Gland, 
terminate  in  it  in  this  manner,  while  others  turn  alide,  or  °-0  over 
it,  and  terminate  in  other  Abforbents  or  in  other  Glands.3 

From  the  oppofite  fide  of  the  Glands,  VefTels  go  out  in  the  man- 
ner they  entered  if,  and  are  termed  Vafa  Efferentxa.  They  are 
frequently,  though  by  no  means  always,  fewer  in  number,  but 
larger  than  the  Vafa  Inferentia. 

v Jjj  - 


156 


Mod  of  the  Abforbents  go  through  feveral  Glands,  but  in  fome 
parts  through  one  only,  before  they  reach  their  general  termina- 
tions. 

The  Lymph  and  Chyle  are  drained  through  the  Glands,  by 
which  they  are  fpppofed  to  undergo  certain  changes,— but  the  na- 
ture of  thefe  changes  has  not  yet  been  afcertained. 

Of  the  Particular  Absorbents. 

The  Superficial  Abforbents  of  the  Lower  Extremities,  confift 
of  numerous  Veffels,  which  lie  between  the  Skin  and  Mufcles. 

They  belong  to  the  Integuments  in  general,  and  are  much  more 
numerous  than  the  Subcutaneous  Red  Veins. 

They  can  be  traced  from  the  Toes,  round  which  they  form  a 
Plexus. 

From  the  Toes,  feveral  Branches,  likewife  forming  a Plexus, 
run  over  the  top  of  the  Foot,  to  the  inner  part  of  the  Leg,  and 
from  that  along  the  correfpondmg  part  of  the  Knee. 

From  the  outer  part  of  the  Foot,  another  Plexus  arifes,  which 
runs  along  the  outfide  of  the  Leg,  where  it  fplits  into  two  Divi- 
lions,  one  cf  which  erodes  obliquely  over  the  fore-part  of  the 
Tibia,  to  the  Lymphatics  at  the  inner  fide  of  the  Knee. 

The  other  Divifion  paffes  partly  to  the  Popliteal  Glands,  fome 
afeending  upon  the  outer  and  back-part  of  the  Thigh. 

The  Popliteal  Glands  are  commonly  two  or  three  in  number, 
and  are  fituated  near  the  Artery  of  the  fame  name,  but  frequent- 
ly they  are  fo  fmall  and  fo  much  buried  in  Fat,  as  to  be  difeover- 
ed  with  difficulty. 

From  the  Sole,  another  Plexus  of  Lymphatics  arifes,  and  joins 
thofe  upon  the  Leg  already  deferibed. 

From  the  i n fide  of  the  Knee  a Plexus  runs  up,  confiding  of 
from  twelve  to  twenty  Trunks,  which  pals  afterwards  on  the  fore 
and  inner-part  of  the  Thigh  to  the  Groin. 

The  greater  part  of  the  Trunks  of  the  1 affc  Plexus,  accompa- 
ny the  Vein  called  Saphena  Major,  and  in  their  pafTage  they  re- 
ceive many  fmall  Branches  from  the  outer  and  back-part  of  the 
Thigh. 

In  the  Groin,  they  fplit  into  Branches  which  penetrate  the  In- 
guinal Glands. 

The  Inguinal  Glands  are  generally  from  fix  or  eight  to  a dozen 
in  number,  and  are  of  very  different  fizes  ; but  fometirnes  ihe 
number  is  fmaller,  in  confequence  of  two  or  more  of  them  being 
united  into  one  large  Gland. 

Of  the  Inguinal  Glands,  fome  lie  in  the  angle  between  the 
Thigh  and  Abdomen,  and  others  a few  inches  faither  down  on 
the  fore-part  of  the  Thigh. 

The  greater  number  are  placed  upon  the  outer  part  of  theTen- 
dinous  Aponeurofis,  the  red  deeper,  being  in  conta£>  with  the 
great  Blood-veffels. 


157 


The  fuperficial  Lymphatics  of  the  Thigh  enter  the  lowed  of  thefe 
Glands  ; one  or  more  of  them,  however,  frequently  pafs  by  the 
full  Glands  they  meet  with,  and  penetrate  others  higher  in  the 
Groin,  and  i’ometimes  a few  do  not  enter  any  Glands  till  they 
go  into  the  Abdomen. 

Into  the  Inguinal  Glands  enter  likewife  the  fuperficial  Lym- 
phatics of  the  upper  and  back-part  of  the  Thigh,  with  thofe  of 
the  Nates  and  of  the  Abdomen  and  Loins. 

The  deep -felted  Lymphatics  of  the  Lower  Extremity  are  fitua- 
ted  among  the  Mufcles, — they  accompany  the  Blood-vtffcls,  and 
are  few  in  number  when  compared  with  the  Subcutaneous  fet. 

In  feveral  places,  one  only  has  been  yet  obferved  on  each  fide 
of  the  Trunks  of  the  Arteries,  though,  in  others,  they  are 
fomewhat  more  numerous,  forming  a Plexus  over  the  Blood- 
velfeis. 

They  arife  from  the  fides  of  the  Toes,  and  from  the  deep  parts 
of  the  Sole,  accompanying  the  Plantar  Arteries  ; and  after  reach- 
ing the  Leg,  they  run  up  with  the  pofterior  Tibial  Artery  to  the 
Ham. 

In  the  Ham,  they  lie  clofe  upon  the  Trunk  of  the  Artery,  and 
enter  the  Popliteal  Glands. 

Befides  thefe,  there  are  fimilarbut  fmaller  Lymphatics,  which 
begin  upon  the  upper  part  of  the  Foot,  and  afterwards  accom» 
pany  the  anterior  Tibial,  and  the  Fibular  Arteries,  receiving 
Branches  from  the  deep  parts  of  the  fore  and  outer-fide  of  the 


The  anterior  Tibial  and  the  Fibular  Lymphatics,  terminate 
with  the  pofterior  Tibial  in  the  Glands  of  the  Ham. 

From  the  Popliteal  Glands,  two  and  fometimes  more  Trunks 
of  confiderable  fize  are  fent  out,  which  accompany  the  Femoral 
Artery,  and,  at  different  diftances,  communicate  with  each  other, 
by  Branches  which  pafs  obliquely  acrofs  the  Artery. 

At  the  upper  part  of  the  Thigh,  they  enter  the  undermoft  of 
the  Inguinal  Glands,  where  the  Lymph  of  the  fuperficial  and 
deep-feated  Abforbents  of  the  Limb  is  mixed  and  incorporated. 

The  fuperficial  Lymphatics  of  the  Scrotum  enter  the  upper  and 
inner  Inguinal  Glands,  thofe  deeper  feated  palTing  with  the  Lym- 
phatics of  the  Tefticle  into  the  Abdomen. 

The  fuperficial  Lymphatics  of  the  Penis  begin  at  the  Prepuce, 
and  form  a few  Trunks  which  run  principally  upon  the  Dorfum 
Penis,  receiving  in  their  paflage  Branches  which  turn  round  from 
its  interior  furface. 

In  fome  Subjects,  they  unite  into  Trunks  in  the  middle  of  the 
Dorfum  Penis,  which  afterwards  feparate  into  right  and  left 
parts. 

In  others,  they  are  more  unconnected,  and  in  all  they  appear 
to  divide  at  the  root  of  the  Penis  into  right  and  left  Branches, 


1-55 


p-ailing  into  the  correfponding  Inguinal  Glands,  which  lie  next 
the  Symphyfis  of  the  Pubis. 

The  deep-fated  Lymphatics  of  the  Penis  arife  from  the  Gians, 
and  from  the  Body  of  the  Penis,  and  accompany  the  Arteries  into 
the  under  part  of  the  Pelvis. 

The  Lymphatics  of  the  Eefiicle  are  numerous,  and  are  among 
the  largeft  of  the  Body,  fome  of  them  exceeding  the  fize  of  a 
Ciow-quill. 

They  arife  from  the  Coats  and  Body  of  the  Tefticle,  and  from 
the  Epididymis,  and  run  with  the  Spermatic  Cord  through  the 
Ring  of  the  Abdominal  Mufcle,  to  terminate  in  the  Lumbar 
Glands. — In  their  paffage,  they  have  few  communications  with 
each  other. 

The  Lymphatics  of  the  External  Parts  oj  Generation  in  Women, 
go  partly  to  the  Inguinal  Glands  of  each  tide,  and  partly  through 
the  Rings  of  the  external  oblique  Mufclcs,  in  company  with  the 
round  Ligaments  of  the  Uterus,  and  terminate  in  the  Iliac  or  in 
the  Lumbar  Glands. 

The  Superficial  Lymphatics  of  the  wider  part  of  the  Abdomen, 
thole  of  the  Loins,  Nates,  and  verge  of  the  Anus,  pats  into  the  In- 
guinal Glands,  each  fet  terminating  in  fuch  of  the  Glands  as  lie 
neared  the  parts  to  which  the  Vetfels  belong. 

The  Inguinal  Glands,  having  received  the  Lymphatics  of  the 
Inferior  Extremity,  and  likewife  the  Superficial  Lymphatics  of 
the  External  Parts  cf  Generation,  fend  out  Trunks  fewer  in 
number,  but  confiderably  larger  than  thole  which  entered  the 
Glands. 

The  Valla  Efferentia  of  the  Inguinal  Glands  enter  the  Abdo- 
men under  Pour  art's  Ligament,  in  company  with  the  Inguinal 
and  Iliac  Artery. 

Some  of  them  go  into  the  Glands  fituated  about  the  Iliac  or 
the  Lumbar  blood-vcffsls.  The  Iliac  Glands_  are  frequently  al- 
anoft  as  numerous  as  the  Glands  of  the  Groin,  and  one  of  them 
is  generally  found  larger  than  the  reft,  and  placed  at  the  inner 
ed"e  of  Poupart’s  Ligament.  The  Lumbar  Glands  are  more 
numerous  than  any  of  the  clafl'es  already  deferibed,  and  are  placed 
over  the  Abdominal  Aorta,  Inferior  Cava,  and  bodies  of  the 
Lumbar  Vertebrae. 

Tbe  reft  of  the  Lymphatics  from  the  Lower  Extremity  de- 
feend  at  the  fide  of  the  Pelvis,  near  the  Internal  Iliac  Blocd- 
veifels,  and  pals  through  fome  of  the  Glands  which  are  fituated 
there. 

The  laft-mentioned  Lymphatics  are  joined  by  Abforbents 
from  the  vifeera  of  the  Pelvis  in  general,  efpecially  by  thofe  of 
the  Bladder  and  Veficulse  Seminales  in  the  Male,  and  by  a portion 
of  thofe  of  the  Uterus  and  of  the  Vagina  in  the  Female. 

The  Lymphatics  oj  the  Bladder,  in  both  fexes;  accompany  its 
principal  Blood -veflels,  pafs  through  fome  fmill  Glands  upon 


159 


the  fide  of  it,  and,  at  the  under  part  of  the  Pelvis,  go  into  the 
Glands  which  furround  the  Internal  Iliac  Artery  and  Vetn.^ 

The  Lymphatics  of  the  Uterus  run  in  two  Sets  ; one,  which  Is 
the  larged,  goes  with  the  Hypogaltric,  the  other  with  the  Sper- 
matic Blood-veiTels. 

The  Hypogajlric  Lymphatics  form  a Plexus  which  runs  from 
above  downwards,  into  Glands  fituated  on  the  fides  cf  the  V a- 
gina. 

From  theie  Glands  they  pafs  to  others  which  fur.und  the  In- 
ternal Iliac  Ve!lels,and  then,  intermixing  with  the  Trunks  from 
the  Extremities,  they  terminate  in  the  Thoracic  Du6t. 

The  Lymphatics,  corresponding  with  the  Spermatic  Veflel^, 
terminate  in  the  Lumbar  Glands,  as  in  the  Male. 

The  Lymphatics  of  the  Uterus,  like  its  Blood-vefTels,  are 
much  enlarged  and  of  confequence  eafily  difeovefed,  in  the  Gra- 
vid date. 

The  Lymphatics  of  the  Rectum  go  firft  into  fmall  Glands  which 
lie  between  it  and  the  Os  Sacrum,  and  afterwards  terminate  in  the 
Lumbar  Plexus  £>t  Glands  and  Vefiels. 

Befides  the  Lymphatics  which  lie  on  the  infide  of  the  Exter- 
nal Iliac  Artery,  there  are  others  fituated  on  the  outfide  of  it, 
upon  the  Ploas  Mufele. 

Of  thefe,  one  part  pafles  up  to  the  Lumbar  Plexus,  and  goes 
under  the  Aorta,  in  different  Branches  which  terminate  in  the 
Thoracic  Duft. 

Another  part  paffes  under  the  Iliac  Arteries,  and  appears  upon 
the  Os  Sacrum,  forming  a remarkable  Plexus,  which  goes  through 
many  Glands,  and  is  chiefly  fituated  behind  the  Aorta  and  Vena 
Cava. 

The  Lacteal  Veffels , fo  called  from  conveying  a fluid  like  milk, 
which  is  termed  Chyle , begin  upon  the  inner  Surface  cf  the  In- 
teftines.  Each  Lafleal  takes  it  origin  upon  one  of  the  Villi,  by 
numerous  fhort  radiated  Branches,  and  each  Branch  is  furnifhed 
with  an  Orifice  for  imbibing  the  Chyle. 

From  the  Villi  the  Lafteals  run  a confiderable  way  under  the 
Mufcular  Coat  of  the  Intefrines,  and  then  pafs  obliquely  through 
them,  uniting  in  their  courfe  into  larger  Branches. 

They  follow  the  direction  of  the  Blocd-veflels,  and  their 
Trunks  are  double  the  number  of  the  Arteries, — one  being  fitu- 
ated on  each  fide  of  them. 

Upon  the  outfide  of  the  Inteftines  an  External  Set  appears. 
They  run  between  the  Peritoneal  and  mufcular  Coats,  and  com- 
monly proceed  fomeway  in  the  direftion  of  the  Intelfine,  and 
with  few  ramifications. 

d he  Superficial  and  deep-feated  Lafleals  communicate  in  the 
Subftance  of  the  Inteffines,  and,  after  leaving  them,  comm  nly 
form  a Plexus,  which  runs  between  the  plies  of  theMefentery  and 
Mefocolon,  without  following  the  courfe  of  the  Blood-vefTels. 

Jfa  A 


ICO 

The  LaEleals  of  the  Jejunum  are  larger  and  more  numerous 
than  thofe  of  the  Ilium , the  principal  part  of  the  Chyle  being 
contained  in  this  Inteftine. 

In  their  cotirfe,  they  pafs  through  a great  number  of  Lnfteai 
or  Mefenteric  Glands,  which  like  the  La6teals  themfelves,  are 
largett  and  molt  numerous  in  that  part  of  the  Melentery  which 
belongs  to  the  Jejunum. 

T-Iit  Mefenteric  Glandsare  feated  in  the  Fat  between  the  Layers 
of  the  Mefentery,  near  the  Branchings  of  the  Blood-velfels. 

They  are  commonly  icattered  over  the  Mefentery,  a.  a little 
diltance  from  each  other  ; but  there  are  feldom  any  obferved  with- 
in two  or  three  inches  of  the  Inteltines. 

They  are  of  different  fizes  in  different  parts  of  the  Mefentery, 
fome  being  about  a half,  or  two  thirds  of  an  inch  in  diameter, 
while  others  are  fofmall  as  to  be  traced  with  difficulty. 

Their  Structure  is  the  fame  with  that  of  the  Abl'orbent  Glands 
in  other  parts  of  the  Bodv,  but  they  are  generally  flatter,  and  arc 
of  a white  coLur  when  filled  with  the  Chyle. 

They  are  confidered  by  fome  Authors  as  dividing  the  Laffeals 
into  different  Orders. 

From  the  Inteltines  to  the  Glands,  theLafteals  are  called  Vaffa 
Laclea  Primi  Generis , and  from  the  Glands  to  the  Thoracic 
Duff,  VaJJ'a  Laclea  Secundi  Generis. 

Somedivide  them  into  three  Orders  ; — the  firft  confifting  of  thofe 
which  go  from  the  Inteftines  to  the  Glands,— the  fecond,  of  thofe 
which  run  from  one  fet  of  Glands  to  another,— and  the  third, 
of  thofe  which  pafs  from  the  Glands  to  the  Thoracic  Du£t. 

The  I.afteals  of  the  Small  Intefines , after  paffing  through  the 
different  Gians  in  the  Mefentery,  form  at  laft  one,  and  freo,uent- 
ly  two,  three j or  more  Trunks,  which  accompany  the  Trunk  of 
the  fuperior  Mefenteric  Artery,  till  they  arrive  at  the  right  fide 
of  the  Aorta,  where  they  fometimes  pafs  into  the  beginning  of 
the  Thoracic  Duft  : At  other  times  they  defcend  a little,  and 
join  the  Trunks  from  the  Inferior  Extremities,  to  form  that 
Dt)£l. 

The  Ahforbents  of  the  Great  are  of  an  inferior  fize  in  pro- 
portion to  thofe  of  the  Small  Jnteflines , and  have  feldom,  though 
fometimer,  been  obferved  to  be  filled  with  Chyle. 

In  their  .courfe  they  . o through  the  Mefocolic  Glands,  which 
ate  fituated  between  the  Layers  of  the  Mefocolon,  but  are  gene- 
rally much  lefs  numerous  and  confiderably  fmnller  than  thofe  of 
the  M' ic.'iery,  or  of  moll  other  parts  of  the  Body. 

The  Abforbents  of  the  Caecum,  and  of  the  right  faction  of  the 
Colon  join  thofe  of  the  final  I lilteftines,  about  the  root  of  the 
Mefentery. 

Thole  of  the  left  portion  of  the  Colon  accompany  die  Inferior 
Mefenteric  Arieiy,  and,  communicate  with  large  Lymphatics 
near  its  root. 


16  L 


They  terminate  at  laft  in  the  Lumbar  Glands,  or  go  dire&ly 
into  the  lower  part  of  the  Thoracic  Du£L 

Of  the  Abforbents  of  the  Stomach,  one  fet  runs  upon  its  finally 
and  another  upon  its  great  Curvature,  but  neithe  the  one  nor  the 
other  are  found  to  carry  Chyle,  though  a few  have  been  obferved 
filled  with  it  in  other  animals, — as  the  Dog. 

The  former  of  thefe,  compofedof  Branches  fr  m the  upper  and 
under  Surfaces  of  the  Stomach,  accompany  the  fuperior  Co  onary 
Artery. 

In  their  pafiage,  they  go  through  a few  fmcll  Glands  fituated 
at  the  junftion  of  the  Omentum  Minus  to  the  Stomach,  and,  af- 
ter becoming  larger  they  enter  other  Glands  in  company  witn  the 
deep-feated  Lymphatics  of  the  Liver,  along  with  which  they  ter- 
minate in  the  Thoracic  Duel. 

The  other  fet  pafies  from  the  great  Curvature  of  the  Stomach, 
partly  to  the  right,  and  partly  to  the  left  fide,  and,  as  on  the  fmall 
Curvature,  are  formed  of  Brandies  from  its  oppofite  Surfaces. 

Thofe  on  the  left  fide  receive  the  Lymphatics  of  the  middle 
and  correfponding  half  of  ihe  Omentum  Majus.  Running  to 
the  left  tide  of  the  large  Curvature  of  the  Stomach,  and  palling 
through  one  or  two  fmall  Glands  on  it,  they  go  with  the  Lym- 
phatics of  the  Spleen  and  Pancreas  to  the  Thoracic  Du£t. 

Thofe  of  the  right  fide  receive  the  Lymphatics  of  the  corre- 
fpondinc;  half  of  the  great  Omentum,  and  alfo  pafs  through  one 
or  two  fmall  Gland;  which  lie  dole  to  the  right  Gaftric  Artery. 

In  their  defeent  by  the  Pylorus,  they  meet  the  Plexus  which 
accompany  the  fuperior  Coronary  Artery,  and  run  with  them, 
and  with  the  deep  Lymphatics  of  the  Liver  to  the  Thoracic 


The  Lymphatics  of  the  Liver,  as  in  other  Vifcera,  run  in  two 
fets,  the  fuperncial  of  which  are  numerous,  and  unite  into  Trunks 
in  the  manner  Roots  unite  to  form-,  the  trunk  of  a tree. 

The  fuperficiai  and  deep  fets  communicate  To- freely-,  that  upon 
inje&ing  the  Lymphatics  on  the  external  Surface,  the  deep-feated 
Abforbents  are  readily  filled  from  them. 

The  principal  part  of  the  Lymphatics  upon  the  convex  Sur- 
face of  the  Liver,  go  by  a right  and  left  Plexus  towards  the  Suf- 
penfory  Ligament. 

Running  along  this  Ligament  they  direftly  perforate  the  Dia- 
phragm, after  which  they  pafs  through  Glands  fituated  upon  the 
anterior  part  of  the  Pericardium. 

Other  Lymphatics  from  the  convex  part  of  the  liver  run  to- 
wards the  lateral  Ligaments,  where  they  form  on  each  fide  one  or 
more  Trunks  of  confiderable  fize. 

From  the  lateral  Ligaments  they  pafs  through  the  Subfiance  of 
the  Diaphragm,  and  afterwards  run  forwards  on  its  convex  Sur- 
face, following  the  direclion  of  the  Ribs. — Not  ^infrequently. 


Du&. 


J 62 


tbei'e  Veffels,  in  (lead  of  perforating  the  Diaphragm,  run  down- 
wards and  terminate  in  the  Thoracic  Duff,  within  the  Abdo- 
men. 

In  their  courfe  upon  the  Diaphragm,  they  often  fend  Branches 
backwaids,  which  terminate  in  Glands  upon  the  Efophagus  ; 
—in  other  inftances,  thefe  Branches  are  oblerved  to  go  dire&ly 
into  the  Thoracic  Duft. 

They  receive  Branches  from  the  Subftance  of  the  Diaphragm, 
and,  after  perforating  two  or  three  Glands  upon  its  Surface; 
they  join  the  Trunks  from  the  Ligamentum  Sufpenforium. 

The  Lymphatics  from  the  lateral  Ligaments,  joined  by  thafe 
from  the  Ligamentum  Sufpenforium,  form  either  a principal 
Trunk,  or  a Plexus,  which  runs  up,  J'ometimes  between  the 
Layers  of  the  anterior  Medialtinum,  and,  at  other  times,  in  com- 
pany with  the  internal  Mammary  Bkod-veffels  on  each  fide. 

When  this  trunk  or  Plexus  runs  in  the  anterior  Mediaftinum, 
it  mod  fiequently  terminates  in  the  upper  end  of  the  Thoracic 
Du£l; — fometimes,  however,  it  communicates  with  the  general 
termination  in  the  right  fde  of  the  Neck. 

When  they  accompany  the  internal  Mammary  Veffels,  they 
are  obferved  to  terminate,  the  left  in  the  Thoracic  Du£V,  and 
the  right  .n  the  general  termination  of  that  fide. 

The  Lymphatics  on  the  concave  Surface  of  the  Liver  run  to- 
wards the  Poita,  and  join  the  deep-feated  Set.— One  part  of  them 
goes  over  the  under  Surface  of  the  Gall-bladder,  from  which 
they  receive  numerous  finall  Branches. 

The  deep-feated  Lymphatics  accompany  the  Blood  and  Biliary 
Vefieis,  and  community ing  with  the  Superficial  Abforbents  al- 
ready mentioned,  they  pafs  through  feveral  Glands  fituated 
about  the  f lunk  of  the  Vena  Portae,  and  terminate  in  the  Tho- 
racic DtnTr,  near  the  root  of  the  fuperior  Mefenteric  Artery. 

The  Superficial  Lymphatics  of  the  Spleen  are  remarkably 
finall.  They  pal's  from  its  convex  to  its  concave  Surface,  where 
they  join  the  deep-l'eated  Lymphatics,  which  are  very  confidera- 
ble  in  fize  and  number. 

The  Splenic  Plexus  of  Lymphatics  accompany  the  Splenic  Ar- 
tery, and  go  though  feveral  Glands  of  a dark  colour  fcattered 
along  the  Surface  of  that  Veffel. 

The  Lymphatics  of  the  Spleen  receive  thofe  of  the  Pancreas, 
which  run  into  them  in  a tranfverfe  dire£tion. 

In  their  courfe,  they  unite  with  the  Lymphatics  of  the  Stomach 
and  thole  defcending  from  the  under  part  of  the  Liver;  and  the 
whole  of  them,  near  the  head  of  the  Pancreas,  form  a confidera- 
ble  Plexus.  From  this  Plexus,  Branches  are  fent  off,  fome  paf- 
fing  over  the  Duodenum,  and  others  under  it,  and  all  of  them 
going  into  the  Thoracic  Du£l  near  the  termination  of  the  Lac- 
teals. 

] . . 


163 


The  Lymphatics  of  the  Kidney  are  feldom  feen,  excepting  when 
it  is  enlarged  or  ulcerated,  in  which  cafe  they  may  lometimes  be 
diftirnflly  obfetved. 

The  Superficial  Abforbents  run  from  its  outer  towards  its  in- 
ner edge,  where,  meeting  with  thofe  deep  feated,  they  commonly 
unite  with  them,  and  form  a Plexus  which  accompanies  the  Renal 
Blood-veffels,  after  which  they  pafs  through  fome  of  the  Lumbar 
Gland;,  and  terminate  in  large  Lymphatics  near  the  Aorta. 

The  Lymphatics  of  the  Capfula  Renalis,  which  are  numerous 
in  proportion  to  its  fize,  terminate  in  the  Renal  Plexus. 

All  the  Abforbents  already  defcribed,  excepting  ihofe  from  the 
convex  Surface  of  the  Liver,  terminate  in  the  Thoracic  Du£l 
near  its  beginning. 

The  Thoracic  Duff,  at  its  under  extremity,  is  formed  by  tbe 
union  of  three,  or  fometimes  of  more  principal  Trunks,  the  firft 
of  which  is  ccmpofed  of  the  Lymphatics  of  the  right,  and  the  fe- 
cond  of  thofe  ot  the  left  Inferioi  Extremity: — the  third  Trunk, 
or  fet  of  Trunks,  belongs  chiefly  to  the  Lafteals. 

Thefe  large  Abfoi bents  unite  fo  as  to  form  the  Duff  over  the 
th'rd  Vertebra  of  the  Loin?. 

Sometimes  they  unite  upon  the  fecond  Vertebra  of  the  Loins, 
where  the  Duel  formed  by  them  is  twice  or  thrice  as  large  in  dia- 
meter as  it  is  higher  up. 

Commonly  it  enlarges  again  upon  tbe  firft  Vertebra  of  the 
Loins,  where  it  has  generally  been  called  the  Receptacle  of  the 
Chyle,  and  confidered  as  the  beginning  of  the  Du6l,  being  often 
found  forming  an  oval,  or  Pyriform  bag,  about  the  third  of  an 
inch  in  diameter. 

Thefe  large  Trunks  which  form  the  Thoracic  Dufl  lie  clofe 
upon  the  Spine,  thofe  of  the  right  fide  being-placed  below  the  Right 
Crus  of  the  Diaphragm,  and  thofe  of  the  left  between  the  Aorta 
and  Spine,  while  the  Thoracic  Du£l  itfelf  lies  at  firft  behind  the 
Aorta,  but  afterwards  pafles  from  it  upwards,  and  a l.ttle  to  the 
right  fide,  till  it  gets  before  the  firft  Vertebra  of  the  Loins. 

Here  it  is  fituated  behind  the  Right  Crus  of  the  Diaphragm,  a 
little  higher  than  the  right  Renal  Artery,  from  whence  it  pafles 
upwards,  and  afterwards  appears  in  the  Thorax,  upon  the  fore 
and  right  fide  of  the  Spine,  between  the  Aorta  and  Vena  Azygos, 
where  it  is  fuppofed  to  be  conliderably  afiifted  by  the  llrukes  of 
the  Aorta  in  impelling  its  Fluids. 

In  the  middle  of  the  Thorax,  it  is  fmaller  than  elfewhere  be- 
ing only  about  a line  in  diameter.  After  this  it  gradually  en- 
larges, and,  near  its  termination,  is  about  an  eighth  or  tenth  of 
an  inch  over. 

In  the  Thorax,  it  receives  the  Lymphatics  of  the  Spatia  In- 
tercoftalia,  one  or  two  of  which  accompan:es  e;  ch  of  ne  Inter- 
coftal  Arteries,  and  the  whole  go  through  final!  Glands  placed 


16  i 

near  thefe  Arteries,  but  moil  numerous  about  the  (ides  of  the  Dor- 
fal  Vertebrae,  where  they  form  a fort  of  chain. 

Hue,  likewife,  it  receives  Branches  from  the  Efophagus  and 
Lungs,  the  former  of  which  is  furrounded  with  a number  of 
Glands,  and  with  a remarkable  and  intricate  Plexus  of  Lym- 
phatic Vefi'els. 

The  Superficial  Lymphatics  of  the  Lungs  form  large  Areola:, 
which  have  fmalier  Areolae  within  them,  the  larger  running  chief- 
ly between  the  Lobules,  and  the  fmalier  paffing  over  them  in  fuch 
a manner  as  to  cover  almoft  the  whole  Surface  of  the  Lungs. 

From  the  furface  they  go  to  the  root  of  the  Lungs,  where  they 
pafs  through  the  Bronchial  Glands,  which  have  already  been  ta- 
ken notice  of  in  the  del’cription  of  the  Lungs. 

At  this  place  they  are  joined  by  the  deep-feated  Lymphatics 
which  creep  along  the  Blanches  of  the  Trachea  and  of  the  Pul- 
monary Blood-veflels. 

Through  the  medium  of  the  Bronchial  Glands,  the  Lympha- 
tics of  the  two  fides  of  the  Lungs  communicate  freely  with  each 
other. 

Having  left  the  Glands,  the  principal  part  of  thole  from  the 
Left  Lung  form  a Trunk  of  considerable  (ize,  which  terminates 
in  the  Thoracic  Du£t,  behind  the  bifurcation  rT  the  Trachea. 

The  reft  of  the  Abforbents  of  the  left  Lung  pafs  through 
Glands  behind  the  Arch  of  the  Aorta,  which  are  likewife  com- 
mon to  thofe  of  the  Heart.  They  run  at  laft  by  a principal  Trunk 
into  the  Thoracic  Duft  near  its  termination. 

After  leaving  the  Bronchial  Glands,  the  Abforbents  of  the 
right  Lung  form  a few  principal  Trunks,  one  of  which  common- 
ly afeends  on  the  fore-part  of  the  Vena  Cava  Superior,  and,  nin- 
ning  in  a convcduted  manner,  opens  into  the  Trunk  which  termi- 
nates in  the  Veins  in  the  right  fide  of  the  neck. 

The  reft  of  thele  Trunks  go  into  the  Thoracic  Du£V,  near  the 
bifurcation  cf  the  Trachea. 

The  Abforbents  of  the  Heart  are  fmall,  but  numerous,  and  form 
principal  Trunks  which  accompany  the  Coronary  Arteries,  and, 
like  them,  the  largeft  belong  to  the  left  Ventricle. 

From  the  fide  of  the  right  Coronary  Artery,  an  Abfor’oent 
Trunk  which  correfponds  with  it,  pafl'es  over  the  Arch  of  the 
Aorta  to  a Gland  commonly  found  behind  the  origin  of  the  Ca- 
rotid Arteries 

From  this  Gland  it  goes  afterwards  to  the  general  termination 
in  the  ride  fide  of  the  Neck. 

The  Lymphatic  Trunk  accompanying  the  left  Coronary  Arte- 
ry is  formed  of  two  prr.cipal  Blanches,  one  of  which  runs  in  the 
Groove  between  the  Ventpcks  on  the  fuperior  Surface  of  the 
Heart  : The  other  runs  in  a ftmilar  Groove  on  the  under  fide 

of  the  Heart,  and  having  reached  the  fpace  between  the  Auricles 

' ■ 


165 


and  Ventricles,  turns  round  to  join  the  former  Branch  near  its 
correfponding  Artery. 

The  Trunk  runs  next  to  a Gland  placed  behind  the  Pulmona- 
ry Artery,  between  the  Arch  of  the  Aorta  and  Root  of  the  Tra- 
chea, which,  with  the  others  here  fituated,  is  common  to  the  Ab- 
i'orbents  of  the  Heart  and  Lungs. 

This  Trunk  terminates  at  length  in  the  upper  end  of  the  Tho- 
racic Duff. 

The  Thoracic  Duel,  after  receiving  numerous  Lymphatics 
within  the  Thorak,  and  having  reached  as  high  as  the  third  or 
fourth  Dorfal  Vertebra,  paffes  obliquely  over  to  the  left  fide  of 
the  Spine,  behind  the  Efophagus  and  end  of  the  Arch  of  the 
Aorta,  or  beginning  of  the  Aorta  Defcendens,  till  it  reaches  the 
left  Carotid  Artery. 

After  this,  it  emerges  from  the  Thorax,  and  runs  between  the 
Longus  Colli  Mufcle  and  Internal  Jugular  Vein,  to  about  the 
fixth  Vertebra  of  the  Neck. 

It  now  makes  a turn  downwards,  and,  after  defeending  near 
an  inch,  terminates  in  the  upper  and  back  part  of  the  angle  form- 
ed by  the  left  Interna  Jugular  and  Subclavian  Vein. 

Throughout  its  whole  couife,  it  has  a waving  appearance,  and 
this  becomes  more  confpicuous  in  proportion  as  it  is  diftended  by 
injefiion.  Near  the  middle  of  the  Thorax,  it  not  unfrequently 
fplits  into  two  or  more  branches,  and  fometimes  forms  a Plexus, 
the  Branches  of  which  again  unite  into  a common  Trunk  a little 
higher  up. 

After  emerging  from  the  Thorax,  it  commonly  divides  into  two 
parts,  which  unite  again  previous  to  the  termination  of  the  Duft 
in  the  red  Veins  j and  where  there  is  no  dirifion,  there  ’is  gene- 
rally a Dilatation  or  Sac  at  the  termination. 

Sometimes  there  is  one.  termination  in  the  angle  formed  by  the 
red  Veins,  and  one  or  two  in  the  Subclavian  Vein,  and  now  and 
then,  though  more  feldoro,  in  the  Internal  Jugular,  near  the  an- 
gle- . 

I",  a few  instances,  it  has  been  found  double  through  its  whole 
length,  one  Duff  going  to  the  common  place  of  termination  in 
the  left  fide  of  the  Neck,  and  the  other  in  the  correfponding  part 
in  the  right. 

It  has  all'o,  in  a few  rare  instances,  been  found  terminating  in 
the  Vems  in  the  right  fide  of  the  Neck,  while  a fhort  Trunk,  fi- 
ir.ilar  to  that  commonly  found  there,  has  terminated  in  the  left 
fide. 

The  Superior,  in  a Cmilar  manner  with  the  Inferior  Extremi- 
ties, hat  - two  lets  of  Lymphatics,  one  lying,  immediately  under 
the  Integuments,  and.  belonging  to  the  Skin  and  Cellular  Sub- 
fiance  u:  it,  tne  other  accompanying  the  principal  Bloocl-vef- 

feis,  and  ^longing  ‘o  the  parts  cieep-feated. 

The  Superficial  Lymphatics  are  numerous,  and  are  readily  feen 
in  emaciated  Sub j efts . 


166 


They  arife  from  the  fore  and  back-parts  of  the  Fingers  and 
hand,  by  a confiderable  number  of  Branches,  and  form  an  ex- 
tenfive  Plexus  upon  the  correfponding  fides  of  the  Fore  Arm. 

Thofe  upon  the  anterior  part  of  the  Fore-arm  run  direfitiy  up- 
wards to  the  Arm,  vvlvle  the  Lymphatics  on  its  back-part,  fepa- 
rate  into  twofets,  one  of  which  paffes  obliquely  over  the  Muf- 
cles  on  the  Radius,  and  the  other  over  thofe  on  the  Ulna,  to  join 
the  Lymphatics  on  the  anterior  part  of  the  Fore-Ai  m. 

The  Lymphatics  of  the  Fore- Arm  mn  over  the  bending  of 
the  Elbow,  and  afterwards  afcend  upon  the  fore  and  inner  part 
of  the  Arm,  the  greater  number  of  them  running  near  the  Balilic 
Vein. 

Some  of  them  frequently  pafs  through  fmall  Glands  placed 
along  the  Humeral  Artery,  one  of  which  is  commonly  found  a 
little  above  the  inner  Condyle  of  the  Os  Humeri,  others  do  not 
appear  to  enter  any  Glands  till  they  reach  thofe  of  the  Axilla. 

A few  Lymphatics  accompany  the  Cephalic  Vein,  and  receive 
Branches  from  the  outer  part  of  the  Arm,  and,  after  piffling  be- 
tween the  Peftoral  -and  Deltoid  Mufclcs,  penetrate  Glands  at 
the  under  fide  of  the  Clavicle. 

Of  the  deep-feattd  Lymphatics,  two  commonly  accompany 
each  principal  Artery  in  the  Fore-Arm,  and  thefe  uniting  at  the 
Elbow,  form  two  principal  Lymphatics,  which  accompany  the 
Trunk  of  the  Humeral  Artery. 

Having  reached  the  upper  part  of  the  Arm,  they  enter  the  Ax- 
illary Glands,  where  they  are  joined  by  Lymphatics  which  come 
from  the  Mamma  and  lateral  parts  of  the  Thorax,  after  palling 
through  fmall  Glands  placed  upon  the  under  edge  of  the  former 
and  of  tlie  large  Peiioral  Mufcle. 

Tile  Axillary  Glands  vary  in  number  and  lize  indifferent  per- 
fons.  They  are  fomewhat  fmaller,  and  fewer  in  number  than 
thofe  of  the  Groin.  They  are  generally  furrounded  by  a confi- 
derable quantity  of  Fat,  and  are  fituated  in  the  hollow  between 
the  large  PeiSloral  and  Latiffimus  Dorfi  Mufcles,  adhering  clofely 
to  the  Trunks  of  the  Axillary  Blood- veffel's  and  Nerves. 

From  the  Axillary  Glands  large  Branches  go  under  the  Cla- 
vicle, and  form  a Trunk,  which,  in  the  left  fide,  commonly  joins 
the  Thoracic  DatSl  near  its  termination.  In  the  right  fide,  they 
join  the  fhort  Trunk  which  forms  the  fecond  general  termination 
of  the  Abforbent  Syltem.  Sometimes  this  Trunk,  proceeding 
from  the  Superior  Extremity,  terminates  in  the  Subclavian  Vein, 
at  a little  diftance  from  the  general  termination. 

Tlte  Axillary  Glands  receive  alfo  the  Subcutaneous  Lym- 
phatics from  the  back-part  of  the  Thorax,  and  likewife  the 
Lymphatics  from  the  Integuments  and  Mufcles  of  the  Scapula. 

The  Lymphatics  on  the  outjide  of  the  Head  accompany  the 
Blood-vefTds.  and  pafs  through  Glands  in  their  wayy  to  the 
Neck. 


i6  n 


Thole  palling  down  with  the  Temporal  Artery  go  through 
l'mall  Glands  connected  with  theParotid  Gland,  and  alfo  through 
others  fituated  immediately  under  the  root  of  the  Zygoma. 

The  Lymphatics  which  accompany  the  Occipital  Blood-vefTels 
penetrate  one  or  two  minute  Glands  placed  a little  behind  the 
root  of  the  Ear,  over  the  Maftoid  Prccefs  of  the  Temporal 
Bone. 

The  Lymphatics  proceeding  from  tjie  different  parts  of  the  Face 
accompany  the  Branches  and  Trunk  of  the  Facial  Artery. 

Some  of  them  pafs  through  Glands  fituated  upon  the  outfide 
of  the  BuccinatorMufcle,  while  the  principal  Trunks  go  through 
a number  of  large  Glands  placed  upon, the  outer,  and  alfo  at  the 
under  part  of  the  Lower  Jaw,  at  the  anterior  edge  of  the  Mafl'e- 
ter  Miifcle,  and  about  the  Inferior  Maxillary  Gland. 

The  Lymphatics  from  the  inner  fart  of  the  Nofe  run  principal- 
ly with  the  internal  Maxillary  Artery,  and  pafs  through  Glands 
fituated  behind  the  Angle  of  the  Lower  Jaw,  where  they  are 
joined  by  thofe  which  belong  to  the  inner  parts  of  the  Mouth. 

The  Lymphatics  of  the  Tongue , and  likewife  of  the  Mufcles 
and  other  parts  obout  the  Os  Hyoides,  enter  the  Glands  placed 
behind  the  angle  of  the  Lower  Jaw. 

Lymphatics  have  been  frequently  fearched  for  in  the  Brain, 
but  their  exiftence  in  that  Organ  is  not  yet  fully  afcertained, 
though  rendered  highly  probable,— from  an  appearance  of  Lym- 
phatics'having  been  now  ar.d  then  obferved  upon  the  Surface  of 
the  Dura  Mater,  and  between  the  Tunica  Arachnoides  and  Pia 
Mater,— from  Lymphatics  and  Glands  being  octafienaily  found 
in,  or  immediately  on  the  outfide  of  the  Palfages  of  the  Blood- 
veffels  of  the  Brain, — fiom  fwellings  in  the  Lymphatic  Glands 
of  the  Neck,  following  dd'eafes  of  the  Brain, — from  the  Ab- 
forption  of  Water,  which  has  fometimes  happened  in  Hydroce- 
phalous  cafes,  and — from  their  having  been  found  on  the  Brain 
of  Fifhes. 

From  the  Superficial  and  deep  parts  of  the  Head  in  genera], 
the  Lymphatics  accompany  the  External  and  Internal  Jugular 
Veins  and  the  Carotid  Arteries,  receiving  at  the  fame  time  Branch- 
es from  the  Mufcles  and  other  parts  of  the  Neck. 

The  principal  part  of  thefe  Lymphatics  go  along  with  the  In- 
ternal Jugular  Vein  and  Carotid  Artery,  and  in  their  paffage 
form  a remarkable  Plexus,'  which  goes  through  the  numerous 
Glands  feated  near  the  Blood-vefTels,  compofing  a chain,  from 
which  they  are  termed  Concatenate. 

The  Glandule  Concatenate  are  more  numerous  than  any  other 
fet  of  Glands  in  the  Body,  excepting  thofe  which  belong  to  the 
Mefentery,. 

The  Cervical  Plexus  of  Lymphatics  having  paffed  through  the 
Glandulae  Concatenatae,  unite  at  the  bottom  of  the  Necklnto  a 
Trunk,  which,  in  the  left  fide,  enters  the  Thoracic  Du&  near 


168 


its  termination,  and  in  the  right,  goes  into  the  Trunk,  which 
forms  the  general  termination  of  that  fide. 

The  Trunk  which  forms  this  general  termination  is  only  from 
a quarter  to  half  an  inch  in  length,  but  its  fize  not  much  lefs  than 
that  of  the  thoracic  Du£l. 

It  is  formed  by  Lymphatics  from  the  right  fide  of  the  Liver, 
Diaphragm,  Heart,  and  the  right  Lobe  of  the  Lungs,  by  thofe 
of  the  right  Arm,  right  fide  of  the  Head,  Neck,  and  Thyroid 
Gland  ; the  Lymphatics  of  the  left  fide  of  the  Thyroid  Gland 
forming  a trunk  which  ends  in  the  Thoracic  Du£t. 

Befides  this  common  Termination,  fome  of  thefe  Lymphatics 
occafionally  open  into  the  Internal  Jugular,  or  into  the  Subcla- 
vian Vein,  at  a little  diftance  from  the  angle  formed  by  thefe  two 
Veins. 


y 


16§ 


PART  VI. 


OF  THE 


BLOOD-VESSELS  IN  GENERAL . 


// 


— /> 


The  Blood-Vessels  are  divided  into  Arteries  and  Feins. 

Arteries. 

^"The  Arteries  are  eladic  Canals,  which  convey  the  Blood  from 
th^.Heart  to  the  different  parts  of  the  Body,  and  are  dillinguifh- 
ed  from  the  Veins  by  their  Pulfation. 

They  have  obtained  their  name  from  the  Ancients,  fuppofing 
that  they  carried  the  finer  parts  of  the  Blood  mixed  with  Air,— 
forming  what  they  coniidered  the  Animal  Spirits. 

The  Original  Trunks  of  the  Arteries,  or  thofe  which  arife 
from  the  Heart,  are  two  in  number,  viz.  the  Pulmonary  Artery 
and  Aorta,— all  the  others  being  derived  from  thefe. 

They  are  difperfed  over  the  whole  Body,  and  are  every  where 
furrounded  with  Cellular  Subftance. 

The  principal  Trunks  run  in  the  Centre  of  the  Body,  or  of  the 
Extremities,  where  they  are  lead  expofed  to  danger,— deriving 
fupport  or  defence  from  the  Bones  along  which  they  pafs. 

The  largelt  Arteries  goto  the  Fifcera,  within  the  great  Cavi- 
ties, the  fmaller  ones  to  the  Skin  and  Mufcles , and  thofe  dill 
fmaller  to  the  Bones, — and,  in  a few  places,  they  become  fo  ex- 
tremely minute  as  altogether  to  exclude  the  red  Blood,  carrying 
a colourlefs  Fluid  only. 

The  Arteries  are  didinguifhed,  in  the  Subject,  from  the  Veins, 
by  the  nvbitenefs  of  their  Colour  and  thicknefs  of  their  Coats. 

They  are  compofed  of  different  Layers  or  Coats,  which  are  rea- 
dily feparated  by  Dilfeftion. 

VoL.  II.  P 


170 


In  feveral  parts  of  the  Body,  as  in  the  Pojlerior  Mediafiinum, 
'they  are  l'urrounded  by  a Membrane,  common  to  them  and  to 
■the  neighbouring  Vitcera. 

In  other  parts  of  the  Body,  efpecially  in  young  Subjefts,  they 
are  furrounded  with  to  much  Cellular  Subliance,  as  to  give  them 
the  appcaiance  of  being  mclofed  in  Sheaths, 

The  fill!  of  the  proper  Coats  is  the  External  Membranous , or 
Cellular,  called  alio  by  fonie  Authors  the  Nervous  Coat. 

In  the  large  Arteries,  this  Coat  is  frequently  furnilhed  with 
Eats,  and  is  of  a very  elaJHc  nature.  Owing  to  this  elalficity, 
the  Arteries,  in  receiving  the  Blood  from  the  Heart,  become  di- 
lated and  elongated,  and  ftart  from  their  place,  in  confequence 
.of  wh.ch  they  form  the  Pulfe,  called  alfo  the  Diajlole  of  the  Ar- 
teries. 

The  Second,  or  Middle  Coat,  is  compofed  of  Fibres  Tunning 
in  a ivanfverfe  direftion, — pf  a pale  red  colour, — each  Fibre  ap- 
pealing to  form  only  the  Segment  of  a Circle,  although  the 
whole  conftitute  a Cylinder  round  the  Artery. 

By  the  Contradhlity  of  this,  and  the  elaltic  nature  of  the  for- 
mer Coat,  the  Arteries  are  enabled  to  drive  the  Blood  to  the 
Veins,  in  proportion  as  tiiey  receive  it  from  the  Heart  ; — and  this 
Contra&ion  is  called  the  Syflole  of  the  Arteries. 

The  Third,  ox  Inner  Coat,  is  formed  of  a tranfparent  Mem- 
brane, remarkably  thin,  1'mooth,  and  denle,  by  which  the  Blood 
is  pi  evented  from  traniuding. 

The  different  Coats  of  the  Arteries  are  conne£led  to  each  other 
by  line  Cellular  Subdances,  which  l'ome  Authors  have  confider- 
*d  as  fo  many  Lamellse. 

The  Arteries  are  fupplied  with  their  own  Blood -veffels,  termed 
Yafa  Caforum,  which  come  from  the  nearell  fmall  Branches,  and 
.are  every  where  dtl'perfed  upon  their  external  Surface. 

They  have  alfo  their  Lymphatics,  which,  on  the  large  Arte- 
ries, as  the  Aorta,  are  fo  numerous  as  l'ometimes  tq.  cover  them. 

They  are  likewiie  furnilhed  with  fmall  Nerves,  forming,  in 
feme  parts  of  the  Body,  a Plexus,  which  vanilhes  in  their  ex- 
ternal Coat. 

There  are  no  Calves  belonging  to  the  Arteries,  excepting 
thofe  which  are  placed  at  the  mouths  of  the  Pulmonary  Artery  and 
Aorta. 

Where  the  Arteries  run  a certain  way  without  fending  off 
Branches,  they  are  obfetved  to  be  of  a Cylindrical  form  ; but 
■where  Branches  come  off,  their  Capacity  is  diminifhed,  and  this 
in  proportion  to  the  number  of  their  Ramifications. 

Whenever  an  Artery  divides  into  two  Branches,  the  Areas  of 
thefe  two  Branches,  taken  conjunflly,  are  found  to  be  nearly 
one  half  larger  than  that  of  the  Trunk  from  which  they  iflue. 

When  the  Trunk  and  Branches  of  an  Artery  are  regarded  col- 
JeStvely,  they  appear  evidently  of  a Conical  figure,  the  point  of 


the  Cone  being  formed  by  the  Trunk,  and  the  Balls  by  the 
Branches  of  the  Artery. 

The  Seftion  of  the  Arteries  is  circular; — when  empty,  they 
become  flit,  but  recover  their  round  form  upon  being  diftended 
by  inje£l ion . 

The  angles  at  which  the  Branches  go  off  from  their  Trunks 
are  in  general  in  proportion  to  their  vicinity  to  the  Heart,  and  are 
fuch  as  are  mod  favourable  to  the  parts  they  have  to  f.pply. 

In  the  Trunk  of  the  Body,  or  where  they  belong  to  tender  and 
delicate  Vifcera,  the  angels  are  moreobtufe; — in  the  Extremities, 
'they  are  more  acute,  the  former  circumftance  tending  to  dimimfh, 
and  the  latter  to  increafe  the  force  of  the  Blood. 

The  Arteries  form  many  Divifions  and  Subdivifions  before 
they  reach  their  Terminations,  and  at  lilt  become  invihbie  to  the 
naked  eye. 

The  Divifions  formed  by  suy  particular  Artery  have  been  va- 
rioufly  enumerated  by  different  Authors.— one  reckoning  I'nCm. 
•«t  forty,  and  another,  of  equal  refpeef  ability,  at  twenty  only  ; — 
the  number  of  them,  however,  is  fuch  as  to  allow  them  to  fup- 
ply  the  raoft  minute  parts  of  the  Body. 

The  ftrength  of  the  Arteries  depends  upon' the  thicknefs  of 
their  Coats,  which  is  found  to  vary  in  different  Arteries. — In  the 
Aorta,  the  Coats  are  thick  and  ftrong  ; — In  the  Arteries  of  the 
BrairTand  Spleen,  they  are  thin  and  teudei  ; — but  the  thicknefs 
and  confequent  ftrength  are  propoi tionably  greater  in  the  fmall 
Branches  than  in  the  lar,e  Trunks. 

The  Arteries  run  more  or  lei's  in  a waving  dire&ion,  which 
breaks  the  force  of  the  Blood  in  them,  and  p; events  them  from 
being  drained  by  the  motions  of  the.  parts  to  which  they  belong. 

The  Flexions  are  rnoft  frequent  in  Arttyies  belonging  to 
parts  the  fize  and  iltuation  of  which  are  changeable. 

The  windings  of  many  of  the  Arteries  are  in  proportion  to  the 
degree  in  wb'ch  they  are  diftended,  thoi'e  which  are  nearly  ftraight 
in  theft-  natural  date,  frequently  becoming  lerpentine  when  their 
diftenfion  increafes. 

Several  of  the  large  Arteries  form  communications  with  each 
other,  termed  by  Anatomifts  Anajlomofes  ; but  the  Anaftomofes 
are  more  frequent  among  the  fmail  Branches,  where  they  form  £ 
Plexus  which  leffens  the  danger  of  obftruclion. 

Tite  Anaftomofes  are  moft  frequent  in  the  Skin  and  Membra- 
nous Parts.  In  the  folid  Vifcera,  the  Arteries  run  in  a different 
manner,  being  in  fome  crowded  together  in  the  form  of  Trees  or 
Bufhrs,  in  others  hiving  a ferpenrine  appearance,  and  in  feveral 
forming  Pen ici  11  i , or  little  Brufties,  according  to  the  difpofitioa 
of  the  part. 

The  Arteries  obtain  their  particular  names  from  their  fixa- 
tions, place  of  deft  nation,  &c.  and  the  term  Capillary , as  ex- 
prefiive  of  their  fmallnefs,  is  applied  to  their  minuteft  Blanches. 


172 


The  Diameters  of  the  different  Trunks  and  Branches  of  the 
Arteries,  vary  much  in  different  parts  of  the  Body  ; but  thofe 
of  the  Capillaries  are  more  nearly  equal  to  each  other. 

The  Arteries  terminate  in  the  following  manner,  viz. 

In  red  Veins,  as  is  obferved  by  the  affiftance  of  the  Microfcope 
and  by  Inje&ions  : 

In  Glands  or  Follicles  by  Secretory  Dufts,  which  feparate  a 
Fluid  from  the  general  Mafs  of  Blood. 

In  Exhalent  Veffels,  which  difeharge  their  contents  into  the 
internal  Cavities,  or  upon  the  external  Surface  of  the  Body. 

In  colourlefs  or  Lymphatic  Branches,  which  are  afterwards 
continued  to  the  circulating  Veins,  as  in  the  Cartilages  and 
Cornea. 

The  Ufe  of  the  Arteries  is  : 

To  convey  Blood  from  the  Heart  to  the  different  parts  of  the 
Body  : 

To  affift  in  converting  the  Chyle  into  Blood  : 

To  nourifh  the  Body,  and  promote  its  growth  : 

Toaffiftin  preferving  the  fluidity  of  the  Blood,  and  the  heat 
and  life  of  the  Body  : 

To  form  the  different  Secretions  : and 

To  renew  the  growth  ®f  parts  deftroyed  by  accident  or  difeafe. 
Veins. 

The  Veins  are  elaftic  flexible  Tubes,  returning  the  Blood  from 
the  different  parts  of  the  Body  to  the  Heart, — and  have  no  Pul- 
fation. 

The  Coats  of  the  Veins  are  the  fame  in  number  with  thofe  of 
the  Arteries,  but  are  thinner,  denfer,  and  lefs  elaftic. 

In  the  large  Veins,  as  the  Vena  Cava,  the  Coats  can  be  fepa- 
rated  from  each  other  but  in  the  ftnall  Branches  their  repara- 
tion is  difficult. 

The  Mufcular  Coat  of  the  Veins  being  much  thinner,  loofe 
like  Cellular  Subftance,  and  more  indiftinft  than  that  of  the  Ar- 
teries, has  cccafioned  its  exiftence  to  be  denied  by  many  Au- 
thors. 

The  Veins  are  alfo  furnilhed  with  their  Vafa  Vaforum , fimi- 
lar  to  and  from  the  fame  fource  with  thofe  of  the  Arteries. 

The  C.olour  of  the  Veins  is  fomewhat  blue,  and  when  full  of 
Blood  they  appear  of  a purple  tinge,  in  confequence  of  their 
thinr.efs. 

Their  Size  is  more  than  double  that  of  the  Arteries  to  which 
they  belong,  excepting  the  Pulmonary  Veins,  the  ftze  of  which 
fcarcely  furpaffes  that  of  their  correfpond ing  Arteries . 

In  the  fleffiy  pa'  ts  of  the  Body,  part'cularly  in  the  Extremities, 
they  conftft  of  Tjvo  Sets,  one  deep-feated  accompanying  the 
Arteries,  the  other  running  immediately  under  the  Skin,  and 
termed  Subcutaneous. 


173 


The  Veins  of  the  Thoracic  and  Abdominal  Vifcera  in  general, 
accompany  their  Arteries;  and  the  lame  is  obfervable  in  the 
fmall  Branches  belonging  to  Membranous  parts. 

The  Figure  of  the  Veins  is  fimilar  to  that  of  the  Arteries  ; and, 
upon  comparing  the  Area  of  their  Tiunks  with  the  coileflive 
Area:  of  their  Branches,  like  them  too,  they  are  perceived  to  be 
Conical,  the  Bafe  of  the  Cone  being  formed  by  the  Branches, 
and  the  Apex  by  the  Trunks. 

The  fize  and  number  of  the  Veins  is  fo  much  greater  than  that 
of  their  correfponding  Arteries,  that  when  the  Vcffels  of  a Mem- 
branous part  are  diftended  by  an  Injeftion  of  different  colours, 
the  Veins  are  obferved  in  a great  meafure  to  conceal  the  Arteries  : 
—In  the  Inteftines  however,  the  number  of  the  Arteries  and 
Veins  is  nearly  equal. 

There  is  much  greater  variety  among  the  Trunks  of  Veins, 
with  refpeft  to  fituation  and  divifion  into  Branches,  than  is  ob- 
fervable among  the  Arteries. 

The  variety  in  Nature  is  fuch,  that  the  Veins  of  every  Sub- 
ject differ  a little  from  thofe  of  another. 

( The  Veins  are  capable  of  buffering  greater  didenfion  than  the 
Arteries,  yet  aie  more  frequently  ruptured. 

The  Analtomofes  are  greater  and  more  frequent  in  Veins  than 
in  Arteries,  thofe  of  the  former  being  frequently  by  large 
Tiunks,  whereas  thofe  of  the  latter,  excepting  in  a few  places, 
are  by  fmall  Branches  only. 

Where  the  Veins  are  expofed  to  Mufcular  nftion,  they  are 
furnifhed  with  Valves,  which  are  fern' lunar  Folds  continued  from 
the  inner  fide  of  the  Veff.ls,  and  placed  in  pairs  at  irregular 
didances  their  nature  being  fimilar  to  thofe  of  the  Abforbents. 

Tne  Valves  are  concave  towards  the  Heart,  and  when  clofed  or 
applied  to  each  other,  reprefent  a figure  fomewli3t  like  that  of 
the  fhut  end  of  a thimble. 

Between  the  Valves  and  Sides  of  the  Veins  next  the  Heart,  the 
Bloo  1 infimiates,  and  Cavities  are  formed,  termed  Sinujes  of  the 
Valves,  which  appear  externally  in  the  form  of  Varices. 

The  Valves  are  found  in  the  flefhy  parts  of  the  Body  in  gene- 
ral, but  are  chiefly  fituated  in  the  Veins  of  the  Extremities. 

They  arc  awanting  in  the  Veins  of  the  deep-feated  Vifcera,  viz. 
in  thofe  of  the  Cranium,  Thorax,  and  Abdomen,  excepting 
the  Spermatic  Veins,  and  fometimes  the  Internal  Mammary 
Veins,  and  the  Branches  of  the  Vena  Azygos. 

The  Valves  diieff  the  Blood  towards  the  Heart,  and  prevent 
Regurgitatioa. 

The  life  of  the  Veins  is  — 

To  convey  the  Blood  from  the  extremlt'es  of  the  Arteries, 
with  the  Chyle  and  Lymph,  from  the  Abforbents  to  the  Heart. 

P 2 


VOL.  II. 


DISTRIBUTION  OF  THE  BLOOD  VESSELS. 


Of  the  Pulmonary  Artery  and  Veins. 

The  Pulmonary  Artery  arifes  from  the  right  Ventricle  of  the 
Heart,  and  afcends  behind  the  Sternum,  and  within  the  Pericar- 
dium, inclining-a  little  to  the  left. 

Having  run  as  high  as  the  concave  fide  of  the  Arch  of  the 
Aorta,  it  divides  into  ri.ht  and  left  lateral  Branches,  which 
terminate  in  the  correfponding  tides  of  the  Lungs. 

The  right  Branch  pafies  behind  the  curvature  of  the  Aorta  and 
the  fuperior  Vena  Cava,  and  is  of  courfe  the  longer  of  the  two. 

The  two  Branches  are  difperfed  throughout  the  fubftance  of 
the  Lungs,  by  ramifications  which  accompany  thofe  of  the 
Bronchi. 

From  the  extreme  Branches  of  the  Pulmonary  Artery,  the 
Blood  is  returned  by  coirefponding  Veins. 

The  Pulmonary  Veins  run  contiguous  to  the  Arteries,  and  un- 
like the  other  Veins  in  general,  are  nearly  of  the  fame  fize  with 
their  Arteries. 

In  their  courfe,  they  unite  into  larger  Branches,  which  at 
length  form  four  principal -Trunks, — two  from  the  right,  and 
two  from  the  left  Lung, — which  after  perforating  the  Pericardi- 
um, terminate  in  the  left  Auricle  of  the  Heart. 

General  Courfe  of  the  Aorta  and  Vena  Cava. 

The  Aorta  arifes  from  the  left  Ventricle  of  the' Heart,  and 
fends  off,  at  its  Origin,  the  Coronary  Arteries  formerly  defcri- 
bed . 

Where  it  takes  its  origin,  it  turns  a little,  to  the  right,  and  is 
afterwards  direfled  upwards,  backwards,  and  towards  the  left 
fide. 

It  afcends  as  far  as  the  top  of  the  Thorax,  under  the  name  of 
Aorta  Afcendens,  and  is  afterwards  reflefled  obliquely  back- 
wards over  the  root  of  the  left  Branches  of  the  Trachea,  forming 
what  is  termed  Curvature,  or  Arch  of  the  Aorta. 

It  then  commences  Aorta  Defcendens , which  runs  down  clofe 
upon  the  Spine,  till  it  reaches  the  fourth  Vertebra  of  the  Loins, 
where  it  divides  into  the  two  Iliac  Arteries. 

The  Thoracic  portion  of  the  Aorta  Defcendens  is  fituated  on 
the  fore  and  left  part  of  the  Spine,  between  the  Layers  of  the  Pof- 
terior  Mediaftinum. 

Where  it  pafies  from  the  Thorax  to  the  Abdomen,  it  goes  be- 
tween the  long  Crura  of  the  Diaphragm,  after  which  it  defcends 
more  immediatly  upon  the  fore-part  of  the  Vertebrae, 


175 


The  Aorta  fends  off  Arteries  wli'ch  cany  Blood  to  the  differ- 
ent parts  of  the  Body,  from  whence  it  is  returned  by  Veins  to  the 
Inferior  and  Superior  Vena  Cava, — excepting  what  paffes  to  the 
Coronary  Veficls. 

The  Inferior  Ca-va  is  formed  by  the  union  of  the  two  Venae  Ili- 
•acae,  upon  the  lalt  Vertebra  of  the  Loins,  a little  below  the  Ter- 
mination of  the  defcending  Aorta. 

It  is  fituated  upon  the  foie-part  of  the  Spine,  and  at  the  right 
fide  of  the  Aorta,  which  it  accompanies  for  a considerable  way- 
through  the  Abdomen. 

Near  the  upper  end  of  the  Abdomen,  it  recedes  from  the  Aor- 
ta, and  paffes  behind  the  large  Lobe  of  the  Liver. 

It  perforates  the  Diaphragm  in  its  Tendinous  part,  and  hav- 
ing entered  the  Pericardium,  it  goes  immediately  into  the  right 
Auricle  of  tlte  Heart. 

The  Inferior  Cava  receives  the  Blood  from  the  Inferior  Extre- 
mities, from  the  Pelvis  and  Abdomen,  and  carries  it  to  the 
Heart. 

The  Superior  Cava , — formed  by  the  union  of  the  two  great 
Venae  Subclaviae,  with  the  addition  of  the  Vena  Azygos, — s fi- 
tuated in  the  upper  part  of  the  Thorax,  upon  the  right  fide  of, 
and  a little  more  anteriorly  than  the  afcending  Aorta. 

It  begins  behind  the  Cartilage  of  the  firft  Rib,  fomewhat 
higher  than  the  Arch  of  the  Aorta,  and  has  at  firft  afmall  incli- 
nation towards  the  right  fide. 

After  defcending  about  an  inch,  it  perforates  the  Pericardium, 
and  having  run  down  nearly  twice  this  lpace,  it  enters  the  Right 
Auricle,  oppofite  to  the  termination  of  the  Inferior  Cava. 

The  Superior  Cava  -receives  the  Blood  from  the  Head,  Neck, 
Arms,  and  containing  parts  of  the  Thorax,  and  all'o  carries  it  to 
the  Heart. 


BLOOD-VESSELS  of  the  HEAD,  and  PART  of 
THOSE  OF  THE  NECK. 

Arteries. 

From  the  upper  fide  of  the  Arch  of  the  Aorta,  three  large 
Arteries  arife,  which  fupply  the  Head,  Neck,  and  Superior  Ex- 
tremities. 

Of  theie  three  Arteries,  one  on  the  right  fide,  termed  lnnomi- 
nata,  foon  divides  into  the  Right  Carotid,  and  Right  Subcla- 
vian Artery. 


176 


The  other  two  are  the  Left  Carotid,  and  Left  Subclavian, 
which  tom£-xifFin  feparate  7 lunks. 

Cafotid  Arteries  : The  Carotid  Arteries,  after  emerging 
from  the  Thorax,  run  up  on  each  fide  of  the  Neck,  between  the 
Trachea  and  Interna!  Jugular  Veins,  and  behind  the  Sterno- 
mattoid  Mufcles,  gradually  receding  from  each  other. 

In  the  Neck,  they  do  not  lend  off  any  Blanches  till  they  reach 
the  top  of  the  Larynx,  where  each,  oppofite  to  the  Os  Hyoides, 
divides  into  External  and  Internal  Carotid  Artefes  ; the  former 
fupplying  the  outer  parts  ot  i lie  Head,  the  other  the  Brain. 

The  External  Carotid  is  placed  more  anteriorly,  and 
nearer  the  Larynx,  than  the  Internal,  which  lies  deeper,  and  is, 
at  its  Rout,  the  larger  of  the  two 

7'he  External,  though  frrinller  than  the  other,  appears  as  a 
continuation  of  the  common  Trunk. 

It  runs  up  behind  the  angle  of  the  Lower  Jaw,  and  in  its  paf- 
fage  hcfoie  the  Ear  towards  the  Temple,  is  funk  deep  in  the  fub- 
ftance  of  the  Parotid  Gland,  which  it  fupplies  with  Blood,  and  is 
divided  into  the  following  pi  incipal  Branches,  viz. 

The  Arteria  Laryngea  Superior,  Gutturalis  Su- 
perior, or  Thyroidea  Superior,  which  comes  off  from  the 
Root  of  the  External  Carotid,  and  fometimes  fiom  the  top  of  the 
common  Carotid. 

Itpafl'es  downwards  and  forwards  in  a winding  dire&ien,  and 
fends 

Branches  to  the  Mufcles  about  the  Os  Hyoides  ; — 

To  the  Mufcles,  Jugular  Glands,  and  Skin  near  the  Larynx;— 
and 

To  the  different  parts  of  the  Larynx  itfelf,  the  continuation 
and  principal  part  ot  the  Artery  terminating  in  the  Thyroid 
Gland. 

The  Arteria  Lincualis,  which  is  fent  off  immediately 
above  the  former. — It  goes  forwards  and  upwards  over  the  cor- 
vefponding  Cornu  of  the  Os  Hyoides,  and  under  the  Hyo-gloffus 
Mufcle,  in  a direction  towards  ihe  under  and  fore-part  of  the 
Tongue. — ft  gives 

A final  1 Branch  to  the  Pharynx  ; — 

A Branch,  termed  Ramus  Hyoideus,  to  the  Mufcles  placed  be- 
tween the  Tongue  and  Larynx  ; — 

The  Dorfalts  Lingua;  to  the  Fauces,  Amygdala,  Epiglottis, 

&c.— 

The  Ramus  Sublingualis , which  comes  off  under  the  middle  of 
the  Tongue,  and  is  difperfed  upon  the  Sublingual  Gland  and  ad- 
jacent Mufcles  ; — and 

The  Ramus  Ra/tinus,  which  is  the  p;  incipal  Branch  of  the 
Lingual  Artery,  running  at  the  under  and  lateral  part  of  the 
Tongue,  and  terminating  near  its  point. 


177 


Tfie  Ar.ter.ia  Facialis,  Maxillaris  Externa,  Labi  a- 
LIS,  or  Angularis,  which  alio  runs  forwards,  and  goes  under 
the  Stylo-hyoid,  and  Tendon  of  the  Digaftric  Mufcles.  It  per- 
forates the  Submaxillary  Gland,  mounts  fuddenly  over  the  angle 
of  the  Lower  Jaw,  at  the  underand  fore-part  of  the  Mafl'eter 
Mufcle,  from  whence  it  proceeds  in  a tortuous  manner  towards 
the  inner  corner  of  the  Eye. 

In  this  courfe,  it  fends  the  following  Branches  to  the  adjacent 
parts. 

The  Palatina  Inferior , which  runs  upwards  upon  the  fide  of 
the  Pharynx.— 

A Branch  to  the  Tonfil,  &c. — 

Branches  to  the  Inferior  Maxillary  Gland  ;— 

Small  Branches  to  the  root  of  the  Tongue,  to  the  Skin,  Muf- 
cles,  &c.  near  the  angle  of  the  Jaw  ; — 

The  A.  Submentalis,  which  runs  forwards  under  the  Bafe  of 
the  Lower  Jaw,  furnifhing  Branches  to  the  parts  near  it,  and  ter- 
minating on  the  middle  of  the  Chin  ;— 

Upon  the  outfide  of  the  Jaw,— a Branch  to  the  Maffeter  Muf- 
cle ; — 

While  upon  the  Buccinator  Mufcle,— Branches  to  the  Cheek 
and  to  the  lower  part  of  the  Under  Lip  ;— 

Near  the  corner  of  the  Mouth, — the  A.  Coronaria  Inferior  to 
the  Under  Lip  ; and  a little  higher,— 

The  Coronaria  Superior  to  the  Upper  Lip,  from  whence 
Branches  run  to  the  under  part  of  the  Partition  and  Point  of 
the  Nofe. 

The  Coronary  Arteries  run  near  the  edge  of  the  Lips,  where 
meeting  with  their  fellows  of  the  oppofite  fide,  they  form  an  A, 
Coronaria  Labiorum. 

Frequently  one  or  both  Coronary  Arteries  are  larger  than  or- 
dinary, in  which  cafe  thofe  enthe  oppofite  fide  are  proportionally 
fmaller. 

After  fending  off  the  Coronary  Branches,  the  Facial  Artery 
runs  near  the  wing  and  fide  of  the  Nofe. 

From  this  part  of  the  Artery  Branches  are  fent  inwards  to  the 
Nofe,  and  outwards  to  the  Cheek. 

The  Facial  Artery  is  at  laid  loll  upon  the  parts  about  the  inner 
corner  of  the  Eye,  and  middle  of  the  Fore-head. 

The  Phary n gea  Inperior,  whch  is  a fniall  Artery  arifing 
near  the  Lingual  Artery,  and  frequently  from  the  root  of  the  Oc- 
cipitalis. 

After  afeending  fome  way,  it  divides  into  Branches,  which 
are difperled  upon  the  Pharynx,  Fauces,. and  Bafe  of  the  Skull, 
where  fi.me  of  them  enter  the  large  Foramina,  and  fupply  part 
of  the  Dura  Mater. 

The  A.  Occipitalis,  which  arifes  from  the  back-part  of  the 
External  Carotid,  and  at  its  origin  is  concealed  by  the  other  ori- 
ginal Branches  fent  off  from  that  Aitery, 


178 


It  runs  ever  the  beginning  of  the  Interna]  Jugular  Vein,  and 
afterwards  paffes  under  the  Maftoid  Procefs,  and  pofterior  Belly 
of  the  Digaftric  Mufcle. 

It  goes  likewife  under  the  upper  ends  of  the  Trachelo-maftoi- 
deus,  Splenius,  and  Complexus  Mufcles  ; after  which,  it  be- 
comes more  fuperficial,  where  it  runs  near  the  middle  of  the  Oc- 
ciput. 

In  its  courfe,  it  is  very  tortuous,  and  gives  off  different  Bran- 
ches to  the  furrounding  Mufcles  : viz. 

One  which  defcends  along  the  Sterno-maftoid  Mufcle,  and 
communicates  with  the  Thyroid,  Cervical,  and  Vertebral  Arte- 
i ies  ; 

Another  which  paffes,  with  the  Jugular  Vein,  to  the  underand 
back-part  of  the  Dura  Mater  i 

A Twig,  through  the  Foramen  Stylo-maftoideum,  to  different 
parts  of  the  Internal  Ear  : 

A Branch  which  proceeds  to  the  back-part  of  the  Ear,  under 
the  name  of  Auricularh  Pcjlerior  -and 

Another,  of  confiderable  1 ze,  which  defcends  between  the  Tra- 
chelo-maltoideus  and  Complexus  Mufcle?,  and,  after  bellowing 
Twigs  upon  feveral  Mufcles  of  the  Neck,  communicates  with 
the  Cervical  and  Vertrebral  Arteries. 

The  Artery  is  at  laft  difperfed  upon  the  beginning  of  the  Oc- 
cipito-frontalis  Mufcle,  and  Skin  of  the  Occiput,  where  it  com- 
municates with  its  fellow,  and  with  the  Temporal  Artery. 

Sometimes,  a Twig  of  this  Artery  paffes-  to  the  Dura  Mater, 
through  that  final!  Irole  occalionally  found  near  the  Maftoid 
Procefs  of  the  Temporal  Bone. 

■ 7'he  A.  Maxillaris  Interna,  which  goes  off  from  that 
part  of  the  Trunk  which  is  covered  by  the  Parotid  Gland,  and  at 
its  origin  lies  behind  the  middle  of  the  upright  Plate  which  di- 
vides into  the  Condyloid  and  Coronoid  Proceffes  of  the  Lower 
Jaw. 

It  paffes  far  ft  between  the  Jaw  and  External  Pterygoid  Muf- 
cle, and  afterwards  runs,  in  a very  winding  manner,  towards  the 
back-part  of  the  Antrum  Maxillare,  fending  numerous  Branches 
to  the  Parts  belonging  to  both  Jaws. 

At  its  origin,  it  furnifhes  Twigs  to  the  fore-fide  and  adjacent 
parts  of  the  outer  Ear. 

It  then  lends  off  the  A.  Dura  Matris  Media  Maxima,  Menin- 
gca,  or  Spheno-fpir.alis,  which  runs  between  the  External  and  In- 
ternal Carotids,  paffes  through  the  Foramen  Spinale  of  the 
Sphenoid  Bone,  and  fpreads  over  the  furface  of  the  Dura  Mater 
and  infide  of  the  Paretal  Bone,  like  the  Branching  of  a Tree. 

The  Inferior  Maxillary  Branch,  which  runs  in  the  Inferior 
Maxillaiy  Canal,  fending  Branches  to  the  lubftance  of  the  Bone, 
and  to  the  Teeth  ; — the  remainder  of  it  paffmgout  at  the  Ante- 


119 


rior  Maxillary  Foramen,  and  communicating  upon  the  Chin  with 
Branches  of  the  Facial  Artery. 

Branches  to  the  Pterygoid,  Maffeter,  and  inner  part  of  the 
Temporal  Mufcle,  under  the  names  of  A.  Pterygoidea,  Majfe- 
t erica,  and  7 emporales  Profunda  : 

The  A.  Buccales  to  the  Buccinator  Mufcle  and  other  foft  parts 
of  the  Cheek. 

The  A.  Alajealares,  which  run  behind  the  Antrum,  and  fend 
Branches  to  the  foft  parts  furrounding  the  Upper  Jaw.— The 
Maxillary  Artery  fends  other  Branches  which  enter  by  fmall 
Holes  to  the  Antrum,  and  to  the  Subltance  and  back-teeth  of 
the  Jaw  ; one  of  whicli  is  larger  than  the  reft,  and  is  the  Proper 
Al<veolaris. 

The  lnfra-orhitar,  which  pafles  in  the  Cana!  under  the  Orbit, 
giving,  at  its  entrance,  Twigs  to  the  foft  parts  in  the  bottom  of 
the  Orbit,  and  in  its  progrefs,  other  Twigs  to  the  Antrum,  Sub- 
ftance  of  the  Jaw,  and  Fore-Teeth  ; after  which  it  goes  out  at 
the  Foramen  Infra-crbitarium,  and  terminates  on  the  Cheek  by 
fmall  Branches  which  communicate  with  thofe  of  the  Facial  Ar- 
tery- 

The  P alato-maxillary  Branch,  which  paftes  through  the  Fo- 
ramen Palatinum  Porter ius,  and  runs  between  the  OfTeous  and 
Fielhy  parts  of  the  Palate,  fupplying  thefe  with  Branches,  and 
frequently  proceeding  through  the  Foramen  Incifivum  to  the  in- 
ner part  of  the  Ncle. 

The  Superior  Pharyngeal,  which  is  a fmall  Branch  terminating 
in  and  about  the  upper  part  of  the  Pharynx. 

The  Large  Lateral  Nafal,  which  enters  the  Foramen  Spheno- 
palatinum,  and  divides  into  many  Branches  which  fupply  the 
greater  part  of  the  in  fide  of  the  Nofe. 

A.  Temporalis. — The  Trunk  of  the  External  Carotid, 
having  given  off  the  Arteries  already  mentioned,  pafles  up  be- 
tween the  Meatus  Auditorius  and  root  of  the  Zygoma,  and  forms 
the  Temporal  Artery,  named  alfo  Temporalis  Externa,  or  Super- 
ficialis  from  the  root  of  which  are  lent  off, 

The  Pranfv  erf  alls  Faciei,  which  proceeds  forwards  under  the 
Zygoma,  fupplying  a large  portion  of  the  Cheek,  and  communi- 
cating with  the  Facial  and  Infra-orbitar  Arteries  : 

Some  fmall  Branches  to  the  Articulation  of  the  Jaw  : 

Several  fmall  Branches  to  the  root  of  the  Ear,  part  of  which 
are  difperfed  upon  the  External  Meatus  and  Membrana  Tym- 
pani, — I'ome  Twigs  penetrating  as  far  as  the  inner  Ear. 

A little  above  the  root  of  the  Zygoma,  where  the  Puliation 
of  the  Temporal  Artery  can  be  felt,  and  frequently  even  leen,  it 
divides  into  two  large  Branches,  an  Anterior,  and  Pofierior, 
which  are  placed  fuperficially  between  the  Integuments  of  the 
Head  and  Aponeuroiis  of  the  Temporal  Mufcle, 


180 


The  Anterior.  Branch  proceeds  forwards,  in  a Terpentine 
direftion,  to  the  fide  and  upper-part  of  the  Forehead,  fupplying 
the  Skin  and  Mufcles  near  it,  and  communicating  with  Branches 
of  the  Facial  and  Occular  Arteries,  and  with  thofe  of  its  Fellow 
on  the  oppofite  fide  of  the  Head. 

The  Posterior  afcends  obliquely  backwards,  giving  a few 
Branches  to  the  upper  part  of  the  Ear,  but  is  chiefly  difperfed  on 
the  Integuments  and  Mufcles  upon  the  lateral  part  and  crown  of 
the  Head,  communicating  with  its  fellow  of  the  fame  and  of  the 
oppofite  fide,' and  alfo  with  the  Occipitalis,  by  numerous  Ramifi- 
cations. 

Internal  Carotid  Artery. 

The  Internal  Carotid, — fometimes  termed^.  Cerebra- 
Jis,~ is  arched  back  at  its  origin,  and  then  afcends  in  a waving 
direftion  on  the  fore-part  of  the  Reftus  Capitis  Anterior  Major 
Mufcle,  as  far  as  the  Foramen  Caroticum,  without  giving  ofP 
any  Branches. 

At  the  Bafe  of  the  Cranium,  it  makes  a fudden  turn  forwards, 
and  enters  the  Carotic  Canal  of  the  Temporal  Bone  : While  in 
the  Canal,  it  pafles  upwards  and  forwards,  like  the  Canal  itfelf, 
and  is  furrounded  by  a confiderable  quantity  of  Cellular  Sub- 
ftance,  and  by  the  Dura  Mater,  which  form  a Cufiiion  between  it 
and  the  Bone. 

After  leaving  tire  Canal,  it  again  bends  upwards  and  then  for- 
wards, by  the  fide  of  the  Sella  Turcica  ; and  perforating  the  Du- 
ra Mater,  at  the  root  of  the  Anterior  Ciinoid  Procefs,  it  is  fud- 
denly  reflected  obliquely  backwards  and  upwards,  after  which  it 
diviJes  into  Branches. 

Through  the  whole  of  its  courfe,  it  runs  in  a Terpentine  man- 
ner, which  prevents  the  Blood  in  it  from  rufhing  too  quickly 
and  forcibly  upon  the  tender  Subftance  of  the  Brain,  and, — con- 
trary to  the  nature  of  other  Arteries, — it  is  of  a Conical  form, 
though  it  does  not  fend  off  any  Branches,  till  it  enters  the  Cra- 
nium. — 

Wh'Je  at  the  Side  of  the  Sella  Turcica,  it  furniftes  fmali 
Twigs  to  the  Dura  Mater  and  parts  adjacent,  one  of  which  pafles 
through  the  Foramen  Lacerum  to  the  Orbit,  and  another,  accom- 
panied by  a fimdar  Twig  from  the  Meningeal  Artery,  through 
the  Pais  Petrola,  to  the  Tympanum, 

As  foon  as  the  Carotid  perforates  the  Dura  Mater,  at  the  root 
ef  the  Ciinoid  Procefs,  it  tranfmits 

The  Arteria  Ophthalmica,  which  is  the  principal  Ar- 
tery belonging  to  the  Eye  and  its  Appendages. 

The  Ophthalmic,  or  Ocular  Artery,  immediately  after  it  comes 
off  from  the  Carotid,  enters  the  Foramen  Opticum,  and  creeps 
under  the  Optic  Nerve,  included  in  the  Dura  Mater,  towards 
the  outer  part  of  the  Orbit. 


13  l 


After  proceeding  fome  way  through  the  Oj  bit,  it  traverfes  its 
Cavity,  taking  a Spiral  direction  towards  the  Nul'e,  between  the 
Optic  Nerve  and  Mufcles  in  the  upper  part  of  the  Orbit. 

In  tiiis  courfe,  it  tirft  tranfmits  Filaments  ter  the  Dura  Mater 
and  Subftance  of  the  Opri ; Nerve,  arid  to  the  beginning  of  the 
Mul'closin  the  bottom  of  the  Orbit,  after  which  it  gives  off  the 
following  Branches,  viz. 

Toe  Arteria  Lacry  mails,  which  rur.s  at  the  outfide  of  the  Or- 
bit, and  is  chiefly  ldpeif  1 upon  the  Lacrymai  Gland,  fume 
Threads  advancing  to  he  E . e-lids  : 

The  A.  Cent’ alls  Ret  ins,  which  penetrates  the  Optic  Nerve  a 
little  behind  the  Bali  of  the  Eye — runs  in  the  centre  of  the 
Nerve,  and  fpreads  out  into  many  fmall  Branches  upon  the  infide 
of  the  Retina. 

When  the  Nerve  is  cut  acitofs,  the  orifice  of  the  divided  Ai  tery 
is  ohfcrvable,  which,  before  its  nature  was  underltood,  was 
long  known  by  .the  name  of  Fonts  Opticus. 

In  the  Adult,  the  Central  Artery_appears  to  terminate  entirely 
upon  the  Retina  5 but  in  the  Foetus,  after  furnifiling,  at  the  bot- 
tom of  the  Orbit,  the  Branched  proper  to  the  Retina,  the  Trunk 
is  continued  forwards  through  the  axis  of  the  Vitreous  Humour, 
flip p lying  its  Cells  and  Membrane  with  delicate  Filaments,  and 
afterward.  -.breading  but  upon  the  back-part  cf  the  Capfule  of  the 
Lens. 

Its  Branches  are difperfed  upon  the  Lens  in  a radiated  manner, 
and  after  furrounding  it,  fome  of  them  are  lent  forwards  to  the 
Membrana  Pupil  laris. 

File  Arterise  Ciliares , — two  or  fometimes  mare  in  number, — 
which  divide  into  Branches  running  in  a terpentine  direction  a- 
loug  the  onpolite  iides  of  the  Optic  Nerve,  and  dividing  into  the 
Ci Wares  Breves,  and  Ciliares  Longa?. 

The  Ciliares  B'e-ves,  or  Pofteriores, — -formed  not  only  of 
Branches  from  the  original  Ciliary  Trunk,  but  alfo  of  Twigs 
from  she  Mufcular  Branches, — are  numerous.  They  perforate 
the  Sclerotica,  near  the  infertion  of  the  Optic  Nerve,  give  Twio-j 
to  that  Coat,  and  dividing  into  ftill  fmalfer  Branches,  creep  for- 
wards upon  the  Tunica  Choruides, — forming  many  Communica- 
tions with  each  other  3$  they  advance,  and  retiring  gradually  from 
the  convex  to  the  concave  l'urface  of  this  Coat  to  luppiy  the  Iris 
and  Ciliary  Proceffes. 

The  Ciliares  Longs, — which  feldom  confi.ft  of  more  than  two 
Trunks, — perforate  the  Sclerotica  a little  farther  forwards  than 
the  former,  pat's  along  the  Choroid  Coat  to  its  anterior  part,  and 
then  feparate  into  Branches. 

-Befides  the  Ciliares  Breves  et  Longae,  there  is  another  Set, 
termed  Ciliares  Anteriores,  which  are  a few  Arterious  Filaments 
from  the  MufcularBranches,  entering  the  Eye  where  the  Straight 
Mufcles  are  inl'erted. 

Vol.  II.  Q 


1S2 


At  the  root  of  the  Iris,  the  different  fets  of  Ciliary  Arlenes 
unite  into  Arches,  which  form  an  irregular  Circle,  called  Circulus 
Iridis. 

From  this  Circle,  many  Arteries  run  upon  the  Iris,  in  a radia- 
ted terpentine  manner,  towards  the  Pupil,  near  wh;ch  fcveral  of 
them  al-fo  unite  into  Arches  ; and  from  thefe,  Twigs  are  font, 
along  with  the  red  of  the  radiated  Branches,  to  the  inner  edge  cf 
the  Iris. — In  the  Foetus,  they  are  continued  to  the  Membrana 
Pupillaris. 

The  Mufcularis  Superior,  and  Inferior,  which  are  dilperfed 
upon  the  Muteles  and  Fat  of  the  Eye. 

The  C Ethnioidalis  Anterior,  and  Pojlerior,  two  extremely  fmall 
Twigs,  elpecially  the  latter,  which  pafs  through  the  Foramina 
Orbitaria  Interna, — Anterius,  et  Poderius, — to  the  Bones  and 
Membranes  of  the  Nofe. 

The  Supra- orbitalis , or  Frontalis,  which,  emerging  from  the 
Socket,  partes  through  the  Foramen  Supra-orbitat turn,  and  is 
divided  into  two  pans  ; — one  dilperfed  upon  the  Periodeum  of 
the  Fore-head,  the  other  running  to  the  Skin  and  Muicles  on  the 
Fore-head  and  upper  Eye-lid,  and  communicating  with  the  an- 
terior Branch  of  the  Temporal  Artery. 

The  remains  of  the  Occular  Artery  are  continued  to  the  inner 
angle  of  the  Eve,  and  are  difperfed  upon  the  Eye-lids,  Lacrymal 
Sac,  fide  of  the  Nofe,  and  Frontal  Mul'cle,  communicating  with 
the  upper  end  of  the  Facial  Artery. 

Arteries  of  the  Brain. 

The  Arteries  of  the  Brain  conrtd  of  the  two  Internal  Carotids, 
and  the  two  Vertebi als. 

Each  Internal  Carotid,  after  fending  forwards  the  Ocular  Ar- 
tery, gives  a Branch  backwards  to  the  Vertebral,  termed  A.  Com- 
municans,  and  then  divides  into  the  A.  -Anterior,  and  A.  Media 
Cerebri. 

The  A.  Anterior  Cerebri,  turns  towards  its  fellow  of 
the  opportte  fide,  and  commonly  fends  Filaments  to  the  Fitft  and 
Second  Pair  of  Nerves. 

A little  before  the  union  of  the  Optic  Nerves,  the  right  and 
lef  t anterior  Cerebral  Arteries  become  aimed  contiguous,  and 
anaftomofe  by  means  of  a fltort,  but  large  tranfveife  Branch, 
which  forms  part  of  that  Communication  of  Veffels  termed  Cir- 
cus Arteriofus  Willisii. 

From  this  tranfverfe  Branch,  but  more  frequently  front  the 
Anterior  Cerebral  Artery  near  it,  a Branch  is  lent  off,  which  paf- 
fes  into  the  Third  Ventricle,  and  furn'fhes  Twigs  to  the  Septum 
Lucidum,  and  fore-part  of  the  Fornix. 

The  Anterior  Cerebral  Artery  alcends  upon  the  inner  fide  of 
the  anterior  Lobe  of  the  Brain,  and  lends  off  a principal  Branch, 


133 


and  commonly  another  Toon  after,  both  of  which  arch  backward! 
upon  the  inner  flat  furface  of  tire  Hemifphere. 

The  continuation  of  the  Anterior  Cerem  al  Artery  is  termed 
A.  Corporis  Callo/t,  and  is  relieved  back  upon  the  union  of  the: 
Corpus  Caliofum  and  Hemifphere,  as  far  as  the  poiierior  Lobs 
of  the  Brain, 

The  Branches  of  the  Anterior  Cerebral  Artery  at  e divided  in- 
to minute  Ramifications,  which  are  fin'd  fpread  out  upon  the  flat 
furface  of  the  Hemifphere,  arid  afterwards  upon  its  upper  part. 

The  Ramifications  form  mimberleJs  Anallomofes  with  each 
other  upon  the  furface  of  the  Brain,. and  afterwards  oafs,  by  mi- 
nute Filaments,  into  it:  Cortical  and  Medullary  Sub  fiance. 

Befides  the  AnalKunoihs  of  the  different  Branches  of  this  Ar- 
tery on  the  furface  of  the  Hemilphevc,  final  1 Branches  run  acrofs 
the  Corpus  Caflofum,  and  inofculate  with  thofe  of  the  oppofite 
ride. 

The  Arteria  Media  Cerebri,— which  is  larger  than  the 
former,- — runs  outwards  in  a lateral  direction  through  the  FoJJ'a 
of  Sylvius,  to  the  6utei  part  of  the  Brain. 

It  gives  frit  Fi. aments  tu  the  GlanHula  Pitu  t tria  and  parts, 
adjacent  to  it,  and  then  divides  into  principal  Branches,  of  which 
one  let  go  to  the  Anterior,  and  the  other  to  the  Lateral  and  part 
of  the  Pofterior  Lobe  of  the  Brain. 

From  this  Aitery,  one  or  two  Twigs  run  up  into  the  anterior 
Cornu  of  the  Lateral  Ventricle,  and  aflift  in  forming  the  Choroid 
Plexus  of  that  Cavity. 

Upon  the  outer  furface  of  the  Brain,  theBranches  of  this  Af- 
ter}'inofculate  with  each  other,  and  with  thofe  of  the  Anterior 
Cerebral- Artery,  and  then  plunee  into  the  lubffance  of  the  Brain, 
where  they  meet  with  the  deep  Branches  of  that  Artery. 

\ Verteeral  Arteries. 

The  two  Vertebral  Arteries , — which  are  only  a little  fmaller 
than  the  Internal  Carotids, — arife  from  the  Subclavian  Arteries 
at  the  bottom  of  the  Neck. 

Each  of  them,  at  a final!  difiance  from  its  origin,  enters  the 
Canal  formed  for  its  reception  by  the  fix  uppermost  Cervical  Ver- 
tebrae. 

It  alcends  through  the  Neck,  nearly  in  a [Haight  direflion, 
fending  Twigs  outwards  between  the  Veitebiae  to  the  deep  Muf- 
cles  of  the  Neck,  and  others  which  pais  inwards  to  the  Spinal 
Marrow  and  its  Membranes,  by  the  Holes  which  tranfmit  the  Spi- 
nal Nerves. 

Immediately  below  the  Plead,  it  gives  out  more  confitiernble 
Branches  to  the  deep  Mufcies  at  the  back-part  of  the  Neck,  which 
inofculate  with  the  Occipital  Artery. 

At  the  upper  part  of  the  Neck,  it  forms  Contortions  fomewhat 
fimiiar  to,  and  anfweriug  the  fame  purpol’e  with  thole  of  the  In- 
ternal Carotid  Artery. 


18  + 


One  turn  is  formed  upwards  and  outwards,  in  palling  from  the 
third  to  the  iecond  Vertebra  ; and  another  outwards  and  for- 
wards, in  going  between  the  iecond  Vertebra  and  Atlas, 

After  perforating'  the  Atlas,  it  bends  fudden'ly  back,  and  tuns 
in  an  horizontal  direction  in  a Notch  upon  that  Bone. 

Ha  ving  reached  the  Foramen  Magnum  Occipitis,  it  turns  up- 
wards, perforates  the  Dura  Mater,  and  enters  the  Cavity  of  the 
Cranium. 

After  entering  the  Cranium,  it  pafies  with  the  Medulla  Ob- 
longata, ypon  the  Cuneiform  Procefs  of  the  Occipital  Bone,  in- 
clining towards  its  fellow  on  the  other  fide,  and  at  the  beginning 
of  the  Medulla,  the  two  Vertebrals  unite  into  the  Trunk  called 
Eafilar  Artery. 

Upon  entering  the  Skull,  each  Vertebral  Artery  fends  a fmall 
Branch,  termed  A . Meningea  Pofierior , — to  the  pofterior  part  of 
the  Dura  Mater. 

It  then  difperfes  Twigs  to  the  Medulla  Oblongata,  and  fre- 
quently gives  off  the  fmall  Branch  which  forms  the  Pof.erior  Ar- 
tery of  the  Spinal  Manow. 

Near  the  part  where  it  unites  with  its  fellow,  it  fends  down  the 
Anterior  Artery  of  the  Spinal  Marrow. 

From  the  Vertebral,  or  from  the  Bafilar,  or  fumetimes  from 
each,  a principal  Branch  is  fent  off,  named  A.  Cerebelli  PoJIerior, 
or  Inferior , which  pafies  between  the  Cerebellum  and  Medulla 
Oblongata,  and  furnifhes  Branches  to  the  under  part  of  the 
Cerebellum,  to  the  back-part  of  -the  Medulla  Oblongata  and 
Tuber  Annulare,  and  forms  the  Choroid  Plexus  of  the  Fourth 
Ventricle. 

The  Basilar  Artery  runs  along  the  middle  of  the  Tuber 
Annulate,  which  it  (lightly  impreffes,  and  lies  upon  the  Cunei- 
form Procefs  of  theOcc.pital  Bone. 

From  the  Tides  of  this  Artery,  numerous  Filaments  run  tranf- 
verfely,  to  be  difperfed  upon  the  Tuber  and  adjacent  parts 

One  Branch,  larger  than  the  reft,  called  Auditoria  Interna,  paf- 
fes  between  the  two  portions  of  the  Seventh  Pai  r of  Nerves  to 
the  Internal  Organ  of  Hearing. 

At  the  extremity  of  the  Cuneiform  or  Bafilar  Procefs  of  the 
Occipital  Bone,  and  at  the  upperand  fore-part  of  the  Tubar  An- 
nulare, the  Bafilar  Artery  divides  into  four  principal  Branches, 
two  to  each  tide,  and  thefe  go  off  almoft  at  light  angles  from  the 
Trunk,  viz. 

The  A.  Superior,  or  Superior  Cerebelli,  which  turns  round  the 
Crura  Cerebri,  expands  its  Branches  upon  the  upper  part  of  the 
Cerebellum,  and  finks  into  its  fubfiance,  fupplying  alio  the 
Nates,  Tellies,  and  Parts  near  them. 

The  Artcria  Pof.erior  Profunda  Cerebri,  which  fends  Twigs  to 
the  Tuber  and  to  the  Cru.a  Ceiebi'i,  and  unites  with  the  Internal 
Carotid  by  the  Atteria  Communicans. 


It  fuppUes  alfo  Parts  lying  near  the  Third  Ventricle,  and  af- 
tei  wards  turning  round  the  Crura  Cerebri,  paffcs  back,  between 
the  Cerebrum  and  Cerebellum. 

It  ddtributes  its  numerous  Branches  chiefly  to  the  Poifenor 
Lobe  of  the  Brain,  one  Branch  in  particular  penetrating  into  t lie 
posterior  Cornu  of  the  Lateral  Ventricle,  and  with  Branches  of 
the  Internal  Carotid,  forming  the  Arterious  part  of  the  Choroid 
Plexus. 

The  Branches  of  this  Artery  3naftomofe  with  thofe  of  the  an- 
terior part  of  the  Internal  Carotid,  at  the  infide  of  the  Hemif- 
phere, — and  with  thole  of  the  lateral  part  of  that  Artery,  at  the 
outfide  of  the  Heinifphere,  in  the  manner  thefe  do  with  each  other 
in  the  other  parts  of  the  Brain. 

The  Arteria  Communicam , which  unites  the  pofterior  Cerebral 
Branch  of  the  Vertebral  Artery  to  the  Trunk  cf  the  Internal 
Carotid,  and  is  nearly  of  the  fame  diameter,  but  longer  than  that 
tranfverfe  Artery  which  conne£ds  the  anterior  Branches  of  the 
Internal  Carotid. 

It  lends  minute  Threads  to  the  Crura  Cetebri,  See.  and  con-  - 
tributes  to  the  formation  of  the  Circle  of  Willis, — or  that  kind 
of  Communication  by  which  the  blood  or  Injefled  Matter  can 
pafs  readily  acrofs  from  one  Internal  Carotid  to  the  other; — or 
from  thele  backwards  to  the  Bail  la  r Artery. 

Veins  of  the  Head  and  of  Part  of  the  Neck. 

The  V sins  which  return  the  Blood  from  the  Arteries  of  the 
Head  and  Neck,  unite  into  the  following  Trunks,  viz. 

• ;-e  Facial  Vein,  which  ds  formed  by  the  Frontal  Ve.n,  and 
l / an  intricate  Plexus  of  Branches  upon  the  Face. 

It  winds  obiiquely  downwards  and  outwards,  at  a diftxnce 
r.  om  the  Artery  ; but  in  crofting  the  Jaw,  it  goes  clofe  by  the 
outride  of  it,  and  terminates  in  the  External  jugular  Vein., 

The  ‘Temporal  Vein,  formed  by  l'uperficial  and  deep  Branches 
’rom  the  tides  and  upper  part  of  the  Head,  and  uwnaig  do  wn 
upon  the  Temple  at  fo me  diftance  from  the  Artery. 

The  Blanches  of  the  Temporal  Vein  form  large  Anaftom.  fes, 
before,  with  thofe  ot  the  F.ontal  Vein;  above,  with  their  fel- 
lows oa  the  other  fide;  and  behind,  with  the  Branches  of  the 
Occipital  Vein. 

The  Trunk  defeends  at  the  fore-part  of  the  Ear,  and,  along 
v ith  the  Artery,  is  funk  in  the  fubitar.ee  of  the  Paiotvd  Gland. 

In  its  descent  before  the  Meatus  Auditor  us  Externus,  it  re- 
ceives Branches  fiom  the  Ear,  Parotid  Gland,  and  Cheek,  cor- 
iefpondin  r with  the  A: teries  fent  to  thele  Part*  front  the  Carotid 
or  Temporal  Artery. 

At  the  under  part  cf  the  Lower  Jaw,  the  Facial  and  Tempo- 
ral Veins  commonly  unite  and  form  the  External  JugaJar. 


The  External  "Jugular  Vein  receives  the  following  branches  at 
the  iijipei  part  of  he  Neck,  viz. 

Branches  of  the  Internal  Maxillary  Vein,  the  principal  part 
term!  ating  in  the  Internal  Jugular. 

'The  Lingual  Vein,  one  Branch  of  which,  termed  Ranina  from 
its  complexion,  is  fcen  under  the  Tongue,  and  is  that  Vein 
which  i-  opened  in  the  Venel’eflion  of  this  Organ. 

Branches  of  the  Occipital  Vein,  the  reft  palling  to  the  Internal 
Jugular,  and  Verve  ral  Vein,,  and  fometimes  alfo  communica- 
ting by  a For:. men  Mallo'deuin  with  the  Lateral  Sinus. 

The  Trunk  of  the  External  Jugular  Ve:n  tlefcends  in  the 
Neck,  between  the  P-latyfma  Mymdes  and  Sterno-maftoid  Muf- 
cles,  receives  in  its  couife  Branches  from  the  adjacent  parts,  and 
terminates  in  the  Subclavian  Vein. 

In  the  formation  and  termination  of  this  Vein,  there  is  great 
vaiiety  in  different  Subjects. 

It  .frequently  happens  that  me  ft  of  the  Ramifications,  which 
commonly  run  from  the  Face  and  Throat  into  this  Veit),  go  to 
the  Internal  Jugular. 

Often  the  Facial  Vein  goes  into  the  Internal  Jugular,  and  the 
Temporal  continued  forms  the  External  Jugular. 

Sometimes  one  of  the  External  Jugulars  terminates  in  the 
ufual  way,  and  the  other  mi  the  Internal  Jugular. 

In  feme  rare  cafes,  the  External  jugulars  have  both  been 
found  terminating  in  one  fide  of  the  Neck. 

Anterior  External  Jugular  Vein.  Bcfides  the  Vein  commonly' 
called  External  Jugular,  a fmall  Subcutaneous  Vein,  termed 
Anterior  External  Jugular , defeends  in  the  fore-part  of  the 
Neck,  receiving  Bl  anches  from  the  adjacent  parts,  and  termina- 
ting in  the  Subclavian  Vein. 

Veins  of  the  Eye  and  its  Appendages. 

The  Blood  fentto  the  Contents  of  the  Orbit  is  returned  paif- 
ly  to  the  Facial  Vein  at  the  inner  corner  of  the  Eye,  but  chiefly 
to  the  proper  Ocular  Vein,  which  terminates  in  the  Cavernous 
Sinus  by  the  following  Veins,  viz. 

'The- Vena  Centralis  Retina,  which  is  formed  by  many  fmall 
Branches  expanded  upon  the  inner  furface  of  the  Retina  along 
with  thofe  of  the  coi  refponuing  Artery. 

The  Vena  Centralis  enters  the  Optic  Nerve,  where  the  Artery 
leaves  it  ; and  a little  behind  the  Ball  of  the  Eye,  it  emerges  from 
the  Nerve,  and  runs  between  it  and  the  Sheath  which  covers  it, 
receiving  many  Twigs  from  the  Nerve  and  its  Membranes. 

It  paftes  afterwards  tinder  the  Fafciculus  of  Nerves  which  be- 
longs to  the  Eye,  and  terminates,  fometimes  in  the  Ocular  Vein, 
but,  in  general,  dire£lly  in  the  Cavernous  Sinus. 

Front  the  Iris  and  Chorohl  Coat,  the  Blood  is  returned  by  the 
Short  or  Anterior  Ciliary  Veins,  and  by  the  Long  or  Lcjierior 


1ST 


Ciliary  Feins,  and  alfo  by  a principal  let  of  Ciliary  Veins,  termed 
Faja  Fo'ticofa. 

Small  Veins  return  from  the  Iris,  winch  go  under  the  Arteri- 
ous  Circle  to  the  Veins  of  the  Choroid  Coat,  and  communicate' 
with  each  other  ; — ‘but  without  forming  any  Circle,  fueh  as  is 
found  in  the  Eyes  of  Oxen,  and  which  correfponds,  in  them,  with 
the  Arterious  Circle. 

The  Anterior  Ciliary  Feins  pafs  from  the  Iris  through  the  Scle- 
rotic Coat,  near  the  fame  part  where  the  Anterior  Ciliary  Arte- 
ries enter. 

The  long  biliary  Feins  are  commonly  two  in  number,  like  the 
Arteries,  and  of  a fmaller  ft ze  than  the  Vorticofe  Veins. 

They  run  from  the  Iris  backwards  along  the  Choroid  Coat 
Communicate  in  their  palTage  by  minute  Branches  with  the  Vorti- 
cofe Veins,  and  afterwards  perforate  the  Tunica  Sclerotica  be- 
hind. 

The  Feutz  Forticofiz,  are  numerous,  and  obtain  their  name 
from  the  Whirls  compofed  by  their  Branches,  the  courfeof  which 
has  been  compared  to  a Jet  d'eazi,  or  to  the  Spiral  Ridges  upon 
the  points  of  the  Fingers,  &c. 

Of  thefe  Veins,  four,  or  fometlmes  five,  are  by  much  the  null 
confpicuous,  the  reft  being  fmaller,  and  having  lei's  of  the  Vor- 
ticofe appearance. 

The  Branches  of  each  of  the  four  principal  Vente  Vorticol’se 
run  in  a clofe  congeries,  unite  at  acute  angles  into  lam  er  Branch- 
es which  have  a curved  direftion,  and  thefe  proceeding  from  all 
fides,  meet  in  a point,  and  form  the  Trunk  of  the  Vein. 

The  Trunks  of  thefe  Vense  Vorticofae,  thus  placed  in  the  cen- 
ter of  their  refpe£live  Whirls  are  fituated  at  the  oppoiite  fides  of 
the  Eye,  and  perforate  the  Sclerotic  Coat  obliquely  near  its  mid- 
dle. 

The  rejl  of  the  Fenee  Forticofae,  or  fmaller  Ciliary  Veins,  com- 
municate with  the  adjacent  larger  Vorticofe  Veins  upon  the  fur- 
face  of  the  Choroid  Coat,  and  alfo  perforate  the  Sclerotica  near 
its  middle. 

After  piercing  the  Sclerotica,  the  different  Vorticofe  Veins 
unite  into  four  or  five  fmall  Ciliary  Trunks,  receiving  a number 
of  minute  Twigs,  which  paint  the  Cellular  Subltance  covering 
the  furface  of  the. Sclerotica. 

The  Ciliary  Veins  run  in  a ferpentine  direction  at  the  oppo- 
fite fides  of  the  Eye,  and  pafs  either  l'eparately  or  united  with 
other  fmall  Veins  in  the  Orbit,  into  the  tiunk  of  the  Ocular 
Vein. 

The  other  Venous  Branches  within  the  Orbit,  correfpond  in  a 
great  meafure  with  their  refpe£tive  Arteries ; fuch  as, 

Branches  from  the  Palpebrae  and  inner  corner  of  the  Eye, 

i he  Lacrymal  Branch  : 

The  0 Ethmoidal  Branches : 


133 


Mufcular  Br  anches, — and  Branches  from  the  Fat  in  the  Orbit, 
and  from  the  Membranes  lining  it. 

The  different  Branches  from  the  Eye  and  its  Appendages  form, 
by  their  union,  the  Ocular  Fein,  which  greatly  exceeds  the  fize 
of  ihe  correfponding  Artery. 

The  Ocular  Vein  forms  large  Anaftomofes,  at  the  inner  cor- 
ner of  the  Eye,  with  the  Facial  Vein,  and  afterwards  paffes  back 
at  the  inner  fide  of  the  Oihit. 

From  the  inner,  it  goes  acrofs  to  the  outer  fide  of  the  Orh:t,  un- 
der the  Attollens  MufcJe ; and  after  runniiu  hack  under  the  An- 
terior Clinoid  Procel's,  coveied  by  the  Third  and  Sixth  Pai,  of 
Nerves,  it  terminates,  under  the  Carotid  Artery,  in  the  Ca- 
vernous Sinus. 

Veins  of  the  Dura  Mater  Corresponding  with  its 
Arteries. 

The  Veins  of  the  Dura  Mater  accompany  their  Arteries,  and 
go  partly  through  Perforations  in  the  Bnfe  of  the  Cranium,  to 
terminate  in  Branches  of  the  External  or  Internal  Jugular  Veins  ; 
— the  reft  go  into  the  neaieft  Sinufes  ©f  the  Brain. 

Veins  of  the  Brain. 

The  fmaller  Veins  of  the  Brain  accompany  the  Arteries. 
Their  Trunks  run  chiefly  between  the  Cii  cumvolutions  of  the 
Brain,  at  a diftance  from  the  Trunks  of  the  Arteries. 

They  terminate  in  the  differerent  Sinufes  of  the  Dura  Mater, 
and  generally  in  an  obhque  dueflion,  which  prevents  the  Blood 
from  returning  into  them. 

The  Sinufes  mull  commonly  found  are  t he  following. 

The  Superior  Longitudinal  Sinus,  which  begins  at  the  under 
part  of  tile  Spine  of  theFiontal  Bone,  runs  along  the  upper  edge 
of  the  Falx,— and  becoming  gradually  wider,  terminates  upon 
the  middle  of  the  Occipital  Bone,  in  the.  two  Lateral  Sinufes. 

It  receives  the  Blood  from  the  upper  part  of  the  Bra  n,  by  feve- 
ral  large  Venous  Trunks,  which  enter  it  obliquely  forwards. 

The  • Torcular  tleroj  hili,  or  Fourth  Sinu  of  the  Ancients, 
chic  fly  firmed  by  the  Venn  Gain',  which  returns  the  Blood 
from  the  Choioid  Plexus,  C i .ora  Striata,  Septum  Lucidum, 
and  other  Internal  pair-  of  the  Brain. 

The  Port  clai  pafles  back  in  the  joining  of  the  Falx  and  Ten- 
toriur  , and  tet  initiates,  along  with  the  Superior  Longitudinal 
Sinus,  i . i he  beg:!  r.ir.g  ■ f the  Lateral  Sinufes. 

TP-.  I'ji  'or  ):nftii<l\  til  Sinus,  a remarkably  final]  one,  fit  th- 
at - i in  the  u nd 1 i;  - lie  Falx. — It  receives  Btai  cues  from 

that  Mu  i ’ i‘m  C us  Callofum  and  pans  of 

the  r..  ' and  ij;i : : es  in  the  beginning  of  tht  Torcu- 
lar el.  _ .* 

-.  ' v - ' Shaft:,  or  S'tafnd  and  Third  Sinufes  of  the 
dinal  and  Torcular  Sinus. 


189 


They  run  at  the  pofterior  edge  of  the  Tentorium,  along  the 
lateral  ridges  of  the  Os  Occipitis,  as  far  as  the  Bale  of  the  Pe- 
trofal  Procelles  of  the  Temporal  Bones,  from  whence  they  wind 
downwards,  pafs  through  the  Foramina  Lacera  common  to  the 
Occipital  and  Temporal  Bones,  and  terminate  in  the  Internal 
Jugular  Veins. 

Frequently  one  of  the  Lateral  Sinufes  is  formed  by  the 
Longitudinal,  and  the  other  by  tile  Torcular  Sinus  ; in  which 
cale,  the  one  is  found  larger  than  the  other. 

The  Lateral  Sinufes  receive  Veins  from  the  Cerebellum  and 
from  the  under  and  back-part  of  the  Cerebrum  ; they  luce- 
wife  receive  the  Blood  from  the  following  frnnll  Sinufes,  lituated 
under  the  Brain,  viz. 

T-he  Circular  Sinus  of  Ridley,  which  is  placed  abaut  the 
Glandula  Pituitaria,  and  frequently  furrounds  it  completely,  re- 
ceiving the  Blood  from  it  and  from  the  adjacent  Bones  and 
Membranes,  and  terminating  in  the  Cavernous  Sinufes: 

Tile  Cavernous  Sinufes,  which  are  lituated  at  the  tides  of  the 
Sella  Turcica,  and  receive  Blood  from  Veins  lying  near  the  lateral 
Blanches  of  the  Internal  Carotid  Arteries,  from  the  Octriar  Veins, 
and  from  the  Circular  Sinus  of  Ridley  : 

The  Cavernous  Sinufes  furround  the  Carotid  Arteries  and 
Sixth  pair  of  Nerves,  and  have  a Cavernous  ftru&ute  within, 
fomewhut  refembling  that  of  the  Penis  : 

The  Superior  Fetrofal  Sinufes,  lituated  upon  the  Ridges  of  the 
Partes  Petrol’s. 

They  receive  fome  finall  Veins  from  the  Dura  Mater  and  Bale 
of  the  Brain,  and  communicate  backwards  with  the  Lateral,  and 
forwards  with  the  Cavernous  Sinufes: 

The  Inferior  Fetrofal  Sinufes,  placed  at  the  roots  of  the  partes 
Petrols. — They  receive  the  blood  from  the  Cavernous,  and  dif- 
charge  it  into  the  ends  cf  the  Lateral  Sinufes. 

Befides  the  Smufts  mentioned  above,  the  following  others  are 
frequently  met  with,  viz. 

A Perpendicular  Occipital  Sinus,  lituated  in  the  Falx  Cerebelii, 
wh'ch  is  fometimes  lingle,  fometimes  double,  and  terminates  in 
the  Lateral  Sinufes.— It  receives  Veins  from  the  Dura  Muter, 
and  communicates  with  the  Vertebral  Veins. 

Anterior  Superior,  and  Anterior  Inferior  Occipital  Sinufes,  pla- 
ced over  the  Cuneiform-Pro  els  of  the  Occipital  Bone,  and  com- 
municating with  the  Inferior  Petrolal  and  Lateral  Sinufes,  ar.d 
with  the  Vertebral  Veins. 

Internal  Jugular  Veins. 

The  Lateral  Sinufes,  having  received  .the  Blood  fent  to  the 
Brain  from  the  Carotid  and  Vertebral  Arteries,  pafs  out  cf  the 
Cranium,  and  form  the  Internal  Jugular  Feins  ; each  of  which, 
at  its  origin  is  bulged  back  in  form  of  a-  Varix,  which  is  termer: 


190 


Diverticulum  and  this  is  lodged  in  a Foffa  at  the  root  of  the  Pars 
Petrofa  of  the  Temporal  Bone. 

The  Internal  Jugular  Vein  defcends  behind  the  Sterno- 
maltoid  Muffle,  upon  the  fore  an  i outer  part  of  the  Common 
Carotid  Arte;)',  with  which  it  is  included  in  a Sheath  oi  Cellular 
Subftance  ; and  is  frequently  a good  deal  dilated  towards  its  un- 
der Extremity,  efpeciaily  in  advanced  life. 

In  its  courts  in  the  Neck,  it  icccives 

Branches  from  the  Pharynx  and  Mufcles  adjacent  to  it: 

The  Internal  Maxillary  Vein  : 

One  or  more  Branches  from  t lie  Occiput: 

The  Lingual  Fein,  which  fometimes  terminates  in  the  External 
J tigular  : 

Ehe  Superior  Laryngeal,  and  now  and  then  the  Inferior  La- 
ryngeal, w hick  more  frequently  goes  into  the  Subclavian,  or  to 
the  top  of  the  Cava. 

The  Internal  Jugular  alfo  receives  Branches  from  the  Mufcles 
cl  the  Neck,  and  at  length  ie:  ruinates  in  the  Subclavian  Vein. 

The  remaining  Blood-Vessels  of  the  Neck.,  with  thoi'e  of 
the  Superior  Extremity  in  General. 

Arteries. 

Subclavian  Artery.  The  Suhclavian  Artery  has  been 
already  obl'eryed  to  a,ril'e  on  the  right  fide,  in  common  with 
the  Carotid  : and  on  the  left,  to  come  oft'  direftly  from  the 
' Aorta.  3 

After  the  Artery  leaves  the  Thorax,  it  paffes  tranfverfely  out- 
wards at  the  under  part  of  the  Neck,  behind  the  under  end  of 
the  Sterno-malloid  Mui'cle,  anil  continues  its  collide  outwards  be- 
tween the  Anterior  and  Middle  Scaleiii  Mufcles,  and  between 
the  Subclavian  Mufcle  and  fir  ft  Rib. 

After  eroding  the  fi-rft  Rib,  it  goes  under  the  Pectoral  Mnf- 
clea  to  the  Axilla,  .where  it  obtains  the  name  of  Axillary  Artery. 

' — Ei  this  court.,  it  lends  oft  the  following  Branches,  viz. 

I he  Vertebral  — The  Internal  Mammary  ; ap.d — The  Supe- 
rior l ntercojial  Artery , — The  'fir ft  of  thefe  has  been  already  de- 
ienbed  ; the  two  others  belong  to  the  inner  part  of  the  Thorax. 

The  Th  yroidea,  or  Gutturalis  Inferior,  which  ari- 
fes  at  tlie  outer  tide  of  the  Vertebral,  and,  afeending  obliquely 
inwards  behind  the  Carotid  Artery,  gives  Branches  to  the  Tra- 
chea and  Efophsgus,  and  Mufcles  near  them  ; but  is  chiefly  dif- 
ptrfcd  upon  the  Thyroid  Gland,  communicating  by  large  Ana- 
ftomofes  with  the  Larynt  ea  Superior. 

The  Cervicalis  Anterior,  which  frequently  comes  oft 
from  the  root  ol  the  Inferior  Thyroid,  and  afeends  in  the 
Neck,  furnifoing  fnperficial  Branches  to  the  Mufcles  which 


191 


go  from  the  Trunk  of  the  Body  to  t'ne  Neck,  and  d-;ep  Bl  anch- 
es to  the  Glands,  Nerves,  No.  lying  on  the  fore  and  lateral 
parts  of  t tie  Cervical  Vertebrae. 

The  Deep  Branches  . analcomofe  with  the  Vertebral  and  Oc- 
cipital Arteries  ; and  fome  palling  through  the  Intervertebral 
Holes  where  the  Nerves  come  out,  communicate  with  the  Spinal 
Arteries. 

The  Cervic.alis  Posterior,  which  arifes  in  common  with 
the  Anterior  Cervicalj  or  with  the  Inferior  Thyroid. — This  is 
larger  than  the  foimtr,  lies  farther  out,  and  runs  in  a winding 
direction  outwards  and  upwards. 

It  fupplies  the  Skin  and  Mufcles  at  the  lateral  and  back-part 
of  the  Neck,  communicates  with  Branches  of  the  Occipital  and 
Vertebral  Arteries,  and  fends  a principal  Branch  downwards  to 
the  parts  about  the  top  of  the  Shoulder. 

The  Dorsalis  Superior  Scapula,  which  comes  fre- 
quently from  the  root  of  the  Thyroid,  and  running  tranfverlely 
behind  the  origin  of  the  Sterno-maftoid  Mufcle,  near  the  Clavi- 
cle,— perforates  the  Notch  in  the  iuperior  Cofta  of  the  Scapula, 
and  expanding  its  Branches  upon  the  Dorf'um  of  that  Bone,  fup- 
plies the  Spinati  and  other  Mufcles  fuuated  there,  and  likewife 
furnifhes  Branches  to  the  joint  of  the  Shoulder. 

The  Axillary  Artery,  lying  in  the  Axilla,  and  furround- 
ed  by  the  Lymphatic  Glands  and  Fat,  and  by  the  large  Nerves 
which  form  the  Brachial  Plexus.  The  Axillary  Artery,  gives 
fome  fmail  Branches  to  the  parts  adjacent  ; — but  its  principal 
Branches  are. 

The  Thoracic.®:,  or  Mammaries  Extern.®, — three  bi- 
four  in  number, — which,  by  fome  Authors,  are  defcribed  by  par- 
ticular names  ; as, 

The  Iboracica  Superior,  which  gives  Branches  to  the  Pc£io- 
rales  and  Serratus,  and  fome  to  the  Intercoftal  Mufcles  : 

The  Thoracica  Longa,  which  fends  Twigs  to  the  Axillary 
Glands  ; but  goes  chiefly  to  the  large  Pectoral  Mufcles,  Mam- 
ma, and  Integuments,  and  inolculates  with  the  Branches  of  the 
Thoracica  Superior. 

The  Iboracica  Humeralis,  or  Thoracic  Artery  of  the  Shoulder, 
which  goes  off  oppofite  the  Thoracica  Superior,  and  divides  fud- 
denly  into  Branches  which  run  tp  the  upper  parts  of  the  Thorax 
near  it,  and  to  the  Mufcles  and  Integuments  lurrounding  the  Ar- 
ticulation : 

The  Thoracica  Axillaris,  which,  when  prefent,  goes  off  from 
or  near  to  the  Thoracica  Humeralis,  and  is  bellowed  upon  the 
Glands,  Fat,  See.  frequently  difperfing  Branches  upon  the  under 
edge  of  the  Subfcapularis  Mufcle. 

The  Scapularis  Interna,  which  foon  divides  into  the 
Proper  Scapular-is  Interna  and  the  Dorfalis  Scapula  Inferior. 


The  Scapularis  Interna  runs  near  the  inferior  edge  of  the  Sca- 
pula, fends  off  many  large  Brandies,  the  principal  part  of  which 
ate  difperfed  upon  the  Latiffimus  Dorfi,  Teres  Major,  and  Sub- 
fcapularis  Mufcles,  and  have  large  Anaftoniofes  with  each  other, 
and  with  the  Superior  Dorlal  Artery  of  the  Scapula. 

The  Dorsalis  Scapulje  Inferior,  immediately  after  lea- 
ving the  Internal  Scapulary  Artery,  turns  round  the  inner  edge 
of  rite  Scapula,  a little  below  its  Cervix. 

Upon  the  Pofterior  Surface  of  the  Scapula,  it  fpreads  out  into 
Branches  of  conftderable  fize,  which  are  difperfed  upon  the  Muf- 
cles covering  the  under  and  back-part  of  the  Bone  ; while  the 
Trunk,  afcending,  inofculates  with  that  of  the  Superior  Dorlal 
Artery  of  the  Scapula,  whereby  an  Arch  common  to  the  two  Ar- 
teries is  formed  at  the  root  cf  the  Acromion. 

The  Cikcumflexa  Anterior,  or  Articularis,  which 
pafks  in  a tranfverle  direction  between  the  Heads  of  the  Coraco- 
bracitialis  and  Biceps  Mufcles,  and  Body  of  the  CC  Humeri, 
immediately  below  the  Joint  of  the  Humerus. 

The  Cikcumflexa,  or  As ticularis  Posterior,  which 
nrifes  dire&ly  oppofite  to  the  fqrmef,  and  is  by  much  the  larger 
of  the  two. 

It  paffes  firfl  between  the  Subfcapularis  Mufcle  and  Teres  Ma- 
jor, and  then  turns  round  between  the  back-part  of  the  Os  Hu- 
meri, and  long  Head  of  the  Triceps,  and  the  Deltoid  Mufcle,  and 
is  djfpeifed  upon  the  Deltoides  and  parts  about  the  Joint  ; — its 
extreme  Branches  anallomofng  with  thofe  of  the  Anterior  Cir- 
cumflex Artery,  fo  as  completely  to  encontpafs  the  Body  of  the 
Bone. 

After  giving  <'1T  thefe  different  Branches,  the  Axillaiy  Artery 
emerges  from  behind  the  edge  of  the  great  Peftoi  al  Mufcle,  and 
runs  along  the  Os  Humeri,  where  it  is  termed  Humeral  or  Bra- 
chial Artery. 

Thu  Humeral  Artery  defeends  behind  the  inner  .edge  cf 
the  Biceps  Mufcle,  covered  by  the  Tendinrus  Apaneurofis  of 
the  Arm,  and  having  the  Triceps  Extenfor  Cubiti  behind.  In 
this  couife,  it  bellows  Branches  to  the  Mufcles  and  Integuments, 
and  to  the  Periolicum  and  Bor.e,  v'z. 

The  Profunda  Humeri,  or  Spiralis,  which  arifes  near 
the  upper  part  of  the  Arm,  at  the  tnfertion  of  the  Latiffimus 
Dorfi  and  Teies  Major  Mufcles,  taking  a Spiral  di  rift  ion  down- 
wards and  outwards,  between  the  Triceps  Mufcle  and  Bone,  and 
terminating  at  the  outer  Condyle  of  the  Os  Ilumeri. 

The  Arteria  Profunda  fends  Branches  chiefly  to  the  Coraco- 
brachialis  and  Triceps  Mufcles,  and  to  thofe  at  the  outer  part 
of  the  Elbow  ; — md  one  of  them,  defeending  at  the  inner  fide  of 
ti.c  Arm,  is  fometimes  fo  conftderable  as  to  form — 

The  Profunda  Inferior  or  Minor.  This  Artery  is  fic- 
quentiy  a Branch  of  the  Profunda  Superior,  but  mote  commonly 


193 


an  orig:nal  Branch  lent  off  from  the  Trunk  of  the  Artery,  near 
the  middle  of  the  Arm. 

It  gives  Branches  to  the  Mufcles  and  other  parts  at  the  infide 
of  the  Arm,  and  terminates  about  the  inner  part  of  the  Os  Hu- 
meri. 

The  Ramus  Anastomoticus  Magnus,  which  comes  off 
a little  above  the-'Elbow,  and  bellows  Branches  to  the  Brachialis 
Interims,  to  the  under  end  of  the  Triceps,  and  to  the  Parts  in 
general  about  the  Elbow-Joint. 

Beiides  thefe,  there  are  feveral  other  Branches  fentin  fucceflion 
from  the  Trunk  of  the  Humeral  Artery  into  the  Mufcles  and  o- 
ther  parts  adjacent. — Thefe  are  Ihorter  than  the  reft,  and  run 
more  in  a tranl’verfe  direction,  efpecially  thofe  to  the  Biceps  Muf- 
cle. — One  fmall  Branch,  termed  Nutritia,  or  Medullaris,  pene- 
trates the  fubftance  of  the  Bone  by  the  paffage  near  its  middle, 
and  fupplies  the  Marrow  and  Parts  which  contain  it. 

The  Trunk  of  the  Humeral  Artery  having  fent  of  the  differ- 
ent Branches  which  belong  to  the  Aim,  paffes  to  the  middle  of 
the  bending  of  the  Elbow,  between  the  Aposeurofis  and  round 
Tendon  of  the  Biceps  Mufcle. 

About  an  inch  below  the  Elbow,  it  commonly  divides  into  two 
principal  Arteries,  the  Radial  and  Ulnar.  It  happens,  however, 
now  and  then,  that  this  Divifion  takes  place  about  the  middle  of 
the  Arm  ; and  in  certain  inftances,  as  high  as  the  Axilla. 

The  Radialis  paffes  over  the  Pronator  Teres  Mufcle,  and 
follows  the  courfe  of  the  Radius  through  the  whole  length  of  that 
Bone 

At  the  upper  part  of  the  Fore-arm,  it  is  covered  by  the  Supi- 
nator Longus  : In  its  defeent,  it  becomes  more  fuperficial,  and, 
at  the  under  part  of  the  Fore-arm,  it  lies  clofe  upon  the  Radius, 
and  immediately  under  the  Skin,  in  confequence  of  which,  the 
Pulfe  is  commonly  felt  in  this  place. 

The  Recurrens  Radialis,  which  is  refletted  to  the  Muf- 
cles and  Parts  of  the  Joint  near  it,  and  anaftomofes  freely  with 
the  Arteria  Profunda  Humeri  at  the  outer  part  of  the  Elbow. 

Numerous  Lateral  Branches,  in  the  defeent  of  the  Artery,  to 
the  Mufcles  and  Integuments,  and  parts  in  general  lituated  about 
the  Radius. 

A Branch  at  the  Wrift,  which  goes  over  the  root  of  the 

Thumb,  and  fometimes  a principal  Branch  along  one  fide  of  it; 

at  other  times,  it  is  difperied  upon  the  Palm  of  the  Hand. 

Small  Branches  to  the  Ligaments,  Bones  and  other  parts  about 
the  Wrift. 

One,  or  fometimes  two  Branches,  termed  Dorfal,  to  the  back- 
part  of  the  Metacarpus  and  Fingers. 

At  the  under  end  of  the  Fore-arm,  the  Radial  Artery  turns 
back  under  the  Tendons  of  the  Extenfors  of  the  Thumb,  and 
Vol.  IL  R 


194 


gets  between  the  roots  of  the  Metacarpal  Bones  of  the  Thumb 
and  Fore-finger,  where  it  divides  into  thite  principal  Blanches, 
viz. 

The  A.  Magna  Pollicis,  which  inns  along  the  fide  of  the 
Tumb  next  the  Fingeis,  and  foineiimes  divides  at  its  root,  into 
two  Branches,  which  lupply  both  lides  of  it. 

The  Radialis  Indicis,  which  runs  along  the  fide  of  the 
Fore-finget  next  the  Thumb. 

The  Palmaris  Profunda,  which  crolfes  the  Hand  between 
the  roots  of  the  Metacaipal  Bones  and  Flexures  of  the  Fingers, 
and  forms  an  Arcus  Profundus,  fi  orh  which  Branches  go  off  to 
the  Interoffei  Mufcles  and  other  deep  parts  of  the  Palm. 

The  Ulnaris  appears  at  firft  as  the  Continuation  of  the 
Trunk  of  the  Humeral  Artery. 

At  its  upper  part,  it  finks  deep  behind  the  flexor  Mufcles  of 
the  Hand,  and  palfes  afterwards  for  fome  way  between  the  Flex- 
or Sublimis  and  Profundus  Digitorum. 

Near  the  Wrift,  it  becomes  more  fuperficial,  and  runs  between 
the  Tendons  of  the  Flexor  Carpi  Ulnaris  and  Flexor  Digitorum 
Profundus,  to  the  Hand. 

In  this  courfe,  it  lends  off  many  Branches  to  the  Fore-arm, 
among  which  the  following  are  the  molt  confiderahle. 

The  Recurrens  Ulnaris,  which  runs  deep  among  the  Flex- 
or Mufcles,  and  foon  divides  into  Branches  which  afcend  and 
fupply  the  Parts  about  the  under  and  inner  fide  of  the  Elbow. — 
In  the  Groove  behind  the  inner  Condyle  of  the  Os  Humeri,  it 
communicates  by  diftinft  Analtomofes  with  the  Profunda  Infe- 
rior, or  with  the  R,:mus  Analtomoticus,  lent  down  from  the  Hu- 
meral Artery. 

The  Interossea  Posterior,  which  comes  off  at  the  upper 
end  of  the  Interofleous  Ligament,  perforating  it  immediately  at 
its  origin,  and  going  to  the  back-part  of  the  Fore-arm. 

From  this  place,  it  lends  upwards  a Recurrent  Branch,  which 
communicates,  upon  the  back-part  of  the  Elbow,  with  the  other 
Recurrent  Arteries,  and  with  the  Branches  lent  down  fiom  the 
Humeral  Artery,  and  forms  along  with  thefe  a Plexus  of  Velfels 
upon  the  back-part  of  the  Joint. 

The  Interolfea  is  afterwards  continued  downwards,  and  is 
chiefly  difperfed  upon  the  Bellies  of  the  External  Mufcles  of  the 
Hand  and  Fingers,  being  commonly  exhaulted  before  it  reach  the 
Wrift. 

The  Interossea  Anterior,  which  comes  off  femetimes 
immediately  below  the  former,  and  at  other  times  in  common 
with  it.  It  is  ccnfiderably  the  larger  of  the  two  ; but  only  a- 
bout  half  the  fize  of  the  Ulnar  Artery  from  which  it  fprings. 

It  runs  clofe  upon  the  Interofleous  Ligament,  and  furmlhes 
Branches  to  the  Mufcles  and  deep  Parts  upon  the  anterior  fide 
•f  the  Fore-arm. 


195 


Near  the  VVrift,  it  perforates  the  Ligament,  and  goes  to  the  Pof- 
terior  fide  of  the  Carpus  and  back,  of  the  Hand,,  dividing  into 
Branches  which  inofculate  with  others  of  the  Polteri or  Inierofle- 
ous  and  Rad;ai  Arteries. 

The  Ulnary  Artery,  having  given  off  its  Recurrent  Branch, 
and  the  Arteriae  Interoffese,  with  many  Lateral  Branches  to  the 
inner  fide  of  the  Fore-arm,  paffes  by  the  fide  of  the  Os  Pififorme, 
and  then  over  the  Annular  Ligament  into  the  Palm,  where  it 
forms  the  Arcus  Volaris  Superficialis. 

At  the  under  end  of  the  Fore-arm,  it  fends  off  a Dorfal  Branch, 
which  psffes  under  the  Tendon  of  the  Flexor  Carpi  Uinaris  to 
the  back  of  the  Hand,  where  joining  with  Branches  of  the  An- 
terior Inrerolfeous  and  Ulnar  Arteries,  it  affifts  in  forming  a 
Plexus  which  l'upplies  the  back-part  of  the  Wrift  and  of  the 
Hand  and  Fingers  with  a number  of  Branches,  which  are  final! 
when  compared  w;'h  thofe  in  the  Palm. 

The  Arcus  Volaris  Sublimis,  or  Superficialis,  is 
placed  with  its  convex  fide  downwards,  and  extends  obliquely 
from  the  root  of  the- Metacarpal  Bone  of  the  Little  Finger  to- 
wards that  of  the  Fit'll:  Bone  of  the  Thumb,  being  covered  by  the 
expanlion  termed  Apnneurojis  Palmaris. 

From  the  Arcus  Volaris,  Branches  are  fent  off  in  the  follow- 
ing order,  viz. 

Several  Small  Branches  to  the  Integuments  and  other  Superfi- 
cial parts  of  the  Palm  : 

A confiderable  Branch  which  fir.ks  near  the  root  of  the  Meta- 
carpal Bone  of  the  Little  Finger,  and  inofculating  with  the  Pal- 
mar Branch  of  the  Radial  Artery,  affilts  in  forming  the  Arcus 
Profundus  : 

A Branch  to  the  inner  fide  of  the  Little  Finger  t 

Three  large  Digital  Branches  which  run  oppofite  to  the  Inter- 
faces of  the  Metacarpal  Bones,  to  the  Roots  of  or  Clefts  between 
the  Fingers. 

At  thefe  Clefts,  each  of  the  Three  Digital  Arteries  is  divided 
into  two  Branches,  one  of  which  Branches  of  each  divifion  runs 
along  the  Anterior  Radial  margin  of  one  Finger,  and  the  other 

along  the  Anterior  Ulnar  margin  of  the  Finger  next  it  ; the 

Three  Digital  Arteiies  thus  fupplying  the  margins  of  all  tile 
Fingers,  excepting  the  inner  margin  of  the  Little  Finger,  and 
the  outer  margin  of  the  Index. 

At  the  Roots  of  the  Fingers,  each  of  the  Digital  Arteries  re- 
ceives a finall  Branch  fiom  the  Arcus  Profundus. 

At  the  Roots  and  Joints,  but  more  particularly  at  the  Points 
of  the  Fingers,  the  Arteries  communicate  by  crofs  Arches,  and 
fend  Branches  to  the  parts  adjacent. 

The  Superficial  Arch  of  the  Palm  commonly  fends  off  one  of 
the  Aiieiies  of  the  Thumb,  and  ultimately  communicates  by  a 
large  Anattomofes  with  the  Root  of  the  Arteria  Magna  Pollicis. 


196 


VEINS  of  the  SUPERIOR  EXTREMITY  and.  of 
PART  of  the  NECK. 

The  Veins  of  the  Superior  Extremities  have  numerous  Values , 
and  are  divided  into  a Superficial  and  a Deep  Set ; the  former 
lying  immediately  under  the  Integuments,  the  latter  accompany- 
ing the  Arteries,  and  taking  their  names  from  them. 

The  Subcutaneous  Veins  have  many  large  Anaftomofes  with 
each  other,  particularly  on  the  Fore-arm,  where  they  unite,  fe- 
parate,  and  re-unite  feveral  times,  thus  forming  a Plexus  by  which 
it  is  furrounded. 

The  Superficial  Veins  from  the  back  of  the  Hand  (one  of 
which,  belonging  to  the  Little  Finger,  was  termed  Salnjatella 
by  the  Ancients)  go  chiefly  to  the  Superficial  Radial,  and  partly 
alfo  to  the  Ulnar  Veins. 

The  Superficial  Radial  Veins  form  the  Vena  Cephalica , and 
the  Superficial  Ulnar  Veins  the  Vena  Bafilica,  at  the  Joint  ot  the 
Elbow. 

The  Superficial  Veins  on  the  Anterior  part  of  the  Fore-arm 
communicate  laterally  with  the  Radial  and  Ulnar  Veins,  and,  in 
their  afeent,  from  a Trunk  termed  Mediana  Longa. 

The  Mediana  Longa,  a little  below  the  bending  of  the  El- 
bow, is  divided  into  Mediana  Cephalica  and  Mediana  Bafilica, 
which  running  obliquely  upwards,  terminate  a little  above  the 
Elbow,  the  former  in  the  Cephalic,  and  the  latter,  eroding  over 
tile  Humeral  Artery,  in  the  Bafilic  Vein. 

Though  this  defeription  correfponds  with  the  general  difliibu- 
tion  of  the  Vt-ins  of  the  Fore-arm  ; yet,  fo  great  is  the  variety 
among  them,  that  they  are  l'carcely  found  to  agree  exactly  in  any 
two  Subjects. 

The  Basilica,  in  its  afeent,  forms  the  principal  Humeral 
Vein,  which  pafl'es  along  the  fide  of  the  Os  Humeri,  a little  to 
the  infide  of  the  Humeral  Artery,  and  receiving  Branches  from 
the  correfponding  fide  of  the  Arm,  it  runs  into  the  Arm-pit,  ancl 
forms  the  Vena  Axillaris. 

The  Cephalica  afeends  at  the  outfide  of  the  Biceps  Mufcle, 
receives  Blanches  from  the  adjacent  parts  of  the  Arm,  and  com- 
municates in  levtral  places  with  the  Bafilic,  and  pafiing  in  the 
Groove  between  the  Large  Pectoral  and  the  Deltoid  Mufcle,  ter- 
minates in  the  Axillary  Vein. 

The  Deep  Veins , termed  alfo  Vence  Satellites,  or  Concotnites  run 
clofe  by  the  fide  of  their  refpeftive  Arteries,  one  lying  commonly 
on  each  fide  of  the  Artery,  and  receiving  the  Blood  from  the  adj- 
acent parts. 

In  various  places  they  anaftomofe  with  each  other  by  fliort 
Branches,  which  crofi  over  the  Arteries. 


197 


Near  the  Joint  of  the  Elbow,  the  Deep  Radial,  Ulnar,  and 
Interojfeous  Veins,  form  a Plexus  over  the  Bifurcation  of  the  Hu- 
meral Artery. 

From  this  Plexus,  a fliort  but  large  Branch  pafles  outwards, 
and  forms  a Communication  with  one  of  the  Subcutaneous  Veins, 
and,  in  general,  the  Communication  is  with  one  of  ihe  Median 
Veins. 

The  Vena  Axillaris,  formed  by  the  Trunks  of  the  Superficial 
and  Deep  Humeral  Veins,  receives  the  Veins  coi  refpondmg  with 
the  Circumflex  Arteries,  and  the  Internal,  and  the  Inferior  Dor- 
fal  Veins  of  the  Scapula. 

A little  higher,  it  is  joined  by  the  Vena  Thoracic#  Extern a, 
and  about  this  place,  changes  its  name  for  that  of  Subclavian 
Vein. 

The  Vena  Subclavia  pafies  betvven  the  Clavicle  and  firil 
Rib,  at  the  inner  fide  of  the  trunk  of  the  Artery,  and  afterwards 
goes  over  the  fore-part  of  the  Anterior  Scalenus  Mufcle,  at  the 
under  end  of  the  Neck. 

After  croffing  the  firft  Rib,  it  receives  the  Vein  correfponding 
with  the  Superior  Dorfal  Artery  of  the  Scapula,  others  wh.ch  foe- 
long  to  the  Cervical  Arteries,  and  alfo  J 'mall  Veins  from  the  Skin 
and  Mufcles  on  the  back  part  of  the  Neck. 

While  fituated  in  the  Neck,  it  likewife  receives  the  External, 
and  then  the  Internal  Jugular  Veins  ; and  near  th  ^ lad  a Vein  of 
confiderable  fize,  which  correfponds  with  the  Trunk  of  the  Ver- 
tebral Artery. 

The  Vertebral  Vein  communicates  within  the  Cranium,  by 
finall  branches,  with  the  Inferior  Petrofal  Sinufes,  or  wrh  Oc- 
cipital Sinufes  ; but  is  chiefly  formed  by  branches  arifing  from 
the  Spinal  Marrow  and  its  Membrane-,  and  from  the  Bones  and 
deep-feated  MufcleS  of  the  Neck. 

Behind  the  top  of  the  Sternum*  the  Subclavian  Vein  frequent- 
ly receives  the  Inferior  Laryngeal  Vein,  the  Anterior  External 
Jugular,  and  the  Internal  Mammary  Vein. — Befides  th.-le,  cue 
Left  Subclavian  receives  alfo  the  Left  Superior  Intercjoflal  Vein  5 
after  which,  it  goes  acrofs  the  Root  of  the  Great  Arteries  fent  up 
from  the  Arch  of  the  Aorta,  and  joins  its  fellow  on  the  oppofite 
fide  to  form  the  Superior  Cava. 


BLOOD-VESSELS  within  the  THORAX. 

Of  the  Blood  .Veflels  within  the  Thorax,  the  Pulmonary  Ar- 
tery ^ and  Veins,  the  Aorta,  the  Coronary  Veflels,  and  the  other 
Veflels  connected  with  the  Heart  have  been  already  noticed. 
Vol.  II.  R 2 


19S 


The  following  are  thofe  which  remain  to  be  defcribed. 

The  Mammaiua  Interna,  which  arifes  from  the  Subcla- 
vian, oppohte  to  the  Inferior  Laryngeal , and  defeends  between 
the  Pleura  and  Cat  tiiages  of  the  TrueRibs,  at  the  edge  of  the 
Sternum  ; — fending  off 

A Small  Reflected  Branch  to  the  Integuments  and  Mufcles  ad- 
jacent to  the  Clavicle  : 

One  or  two  fmall  Blanches,  termed  Thytnica,  to  the  Thymus 
Gland,  and  which,  like  the  Gland  itfelf,  are  moft  eonfiderable  in 
the  Young  Subjeft  : 

A minute  Branch,  termed  Comes  Nervi  Phrenici , which  ac- 
companies the  Phrenic  Nerve,  and  after  giving  Twigs  to  the 
neighbouring  Membranes,  is  diffributed  upon  the  Diaphragm  : 

Some  (mail  Branches,  called  Mediajlince,  and  Pericardia,  to 
the  Mediaftinum  and  Pericardium  : 

Several  Branches  outwards,  to  the  Intercoftal  Mufcles  5 and 
others  between  the  Cartilages  of  the  TrueRibs  at  the  edge  of  the 
Sternum,  to  the  Pe&oral  Mufcles,  Mamma  and  Integuments, 
which  communicate  with  thofe  of  the  Thoracicae  Externa;  : 

A Large  Branch,  at  the  under  end  of  the  Thorax,  which  is 
difperfed  upon  the  Diaphragm. 

The  Mammary  Artery  afterwards  emerges  from  the  Thorax, 
commonly  under  the  Cartilage  of  the  feventh  True  Rib,  and  tuns 
upon  the  back-part  of  the  Reftus  Abdominis  Mufcle,  upon  the 
upper  end  of  which  it  is  difperfed,  after  fendijig  a Branch  to  the 
Oblique  Mufcles  of  the  Abdomen. 

The  Intercostalis  Superior,  which  comes  off  a little 
farther  out  than  the  Mammary,  and  defending  near  the  Spine, 
commonly  divides  into  two  or  three  Branches,  which  fupply  an 
equal  number  of  Intercoftal  Spaces. — It  alft)  fends  a Branch  up- 
wards to  the  Deep  Mufcles  at  the  under  and  f®re-part  of  1 lie 
Neck. 

The  Arteri/e  BrONCHIaleS,  one  in  the  right  and  two  or 
three  in  the  left  fide  of  the  Thorax,  which  are  difperfed  upon 
the  correfponding  fides  of  the  Lungs. 

The  Bronchialis  Dextra,  which  arifes  moft  frequently 
from  the  uppermoft  Intercoftal  Aitery  of  the  Aorta  ; and  the 
Bronchiales  Sinistra,  which  are  of  unequal  fize,  from 
the  fore-part  of  the  Aorta  at  a little  diftance  from  each  othtr. 

The  Bronchial  Arteries  fend  (mail  Branches  to  the  Efophagus, 
to  the  Pofterior  Mediaftinum  and  Pericardium,  and  afterwards 
accompany  thofe  of  the  Trachea  through  the  fubftance  of  the 
Lungs. 

The  Arteries  Esophage/e,  which  are  minute  Branches 
arifing  from  the  Aorta,  and  difperfed  upon  the  Efophagus,  alfo 
fending  Twi  to  the  Pofterior  Mediaftinum. 

The  Intercostales  Inferiores,  which  are  nine  or  ten 
pairs  in  number,  arifing  from  the  back-part  of  the  Aorta,  and 


199 


running  in  the  Grooves  at  the  under  edges  of  the  Ribs,  between 
the  External  and  Internal  Intercoftal  Mufcles. 

They  furnilh  Branches  to  the  Spine  and  Spinal  Marrow,  to  the 
Intercoftal  Mufcles,  Pleura,  See.  alfo  numerous  Branches  to  the 
Mufcles  on  the  back  of  the  Thorax,  and  communicate  with 
thole  of  the  Internal  and  External  Mammary  Arteries. 

Veins. 

The  Blood  fent  to  the  Thorax  by  the  Arterias  Mammarise  In- 
ternae,  Intercoftales,  and  Efophageas,  is  returned  to  the  Heart  by 
the  following  Veins,  viz. 

The  Mammary  Intern  e,  which  accompany  their  corre- 
fponding  Arteries,  and  terminate,  the  Left  in  the  Subclavian,  and 
the  Right  in  this,  or  in  the  top  of  the  Vena  Cava. 

Some  fmall  Veins,  as  the  Pericardiaco-Diaphragmatic,  the 
Thymic  and  Pericardiac,  which,  in  place  of  joining  the  Mamma- 
ry Trunk,  commonly  terminate,  the  Right  in  the  Subclavian,  or 
top  of  the  Cava,  and  the  Left  in  the  correfponding  Subclavian 
Vein. 

The  Venje  Intercostales,  which  are  the  fame  in  number 
with  their  Arteries,  and  accompany  them  along  the  edges  of  the 
Ribs. 

Several  of  the  Lower  Left  Intercoftals  unite  into  a trunk, 
termed  Vena  Azygos,  which  croffes  over  the  Spine  about  the  mid- 
dle of  the  Thorax,— behind,  but  fometimes  before  the  Trunk  of 
the  Aorta, — to  the  right  fide. 

The  Vena  Azygos,  of  Venafine  Pari,  thus  originally  form- 
ed by  the  Lower  Left  Intercoftals,  afeends  on  the  fore- part  of 
the  Spine  over  the  Intercoftal  Arteries,  at  the  right  fide  of  the 
Aorta.  •" 

At  its  lower  extremity?  it  generally  communicates  with  one  of 
the  Lumbar  Veins,  or  with  the  Vena  Renalis  ; and  not  unfre- 
quently  with  the  Trunk  of  the  Inferior  Cava. 

Upon  the  Spine,  it  recei  ves  the  Right  Intercojlals,  and  the  Ripht 
Bronchial  Vein  ; and  turning  forwards  over  the  Root  of  the  Great 
Pulmonary  Veflels  of  that  fide,  it  terminates  in  the  Superior 
Cava. 

The  Upper  Left  Intercostal  Veins,  or  fuch  as  are  not 
received  by  the  Vena  Azygos,  terminate  in  a trunk  on  the  left 
fide,  improperly  called  Left  Vena  Azygos. 

The  Left  Vena  Azygos,  Left  Bronchial,  or  Left 
Superior  Intercostal  Veik,  befides  the  Superior  Intercof- 
tal Branches,  receives  the  Left  Bronchial  Veins  and  Branches 
from  the  Efophagus  and  other  parts  near  it,  and  terminates  in  the 
Subclavian  Vein. 

The  Vena  Cava  Superior, — formed  by  the  union  of  the 
Subclavian  Veins,  with  the  addition  of  the  Vena  Azygos, — paf- 
f'es  down  at  the  right  fide  of  the  afeending  Aorta,  perforates  the 


200 


Pericardium,  and  terminates  in  the  upper  part  of  the  Right 
Auricle. 

Blood-Vessels  of  /^Diaphragm. 

The  Diaphragm  is  fupplied  with  Blood-veflels  from  va- 
rious l’ourci  s,  viz.  thofe  entering  its  upper  part  from  the  Inter- 
nal Mammary,  already  defer  bed  ; alfo  fmall  Branches  from  the 
Intercoftal  and  Lumbar  Arteries.  Its  principal  Branches,  how- 
ever, are  the  Ph  tnic,  01  Diaphragmatic. 

The  Arteri.®  Diaphragmatic^;,  are  two  in  number,  one 
on  each  fide,  winch  aril'e  turn  the  foie  part  of -the  Aorta  as  foon 
as  it  enters  the  Abdomen. 

In  general,  their  oiigin  is  diftir.fl  from  each  other,  but  fome- 
times  by  a common  Trunk;  and  now  and  then,  one  or  both, 
originate  from  the  root  of  the  Ccehaca. 

They'  aftei wards  go  obi  quely  upwards  and  outwards  over  the 
Crura  of  the  Diaphragm,  fpread  out  into  many  Branches 
which  are  chiefly  difperfed  upon  its  Flefhy  lides,  and  inofculate 
with  thole  which  enter  at  its  upper  fui face. 

They  likewife  give  fmall  Branches  to  t lie  Glandulse  Renales,  to 
the  Cardia,  and  parts  in  general  which  lie  near  them. 

The  VENiE  Diaphragmatic^;,  like  their  correfpomling 
Arter.es,  run  upon  .he  under  part  of  the  Diaphragm,  and  termi  . 
nate  in  the  Inferior  Cava,  behind  the  Liver,— the  right  being 
commonly  a little  lower  than  the  left. 


BLOOD-VESSELS  of  the  CHYLOPOETIC,  and 
ASSISTANT  CHYLOPOETIC  VISCERA. 

Arteries. 

The  Arteries  of  thefe  Vifcera,  conlift  of  the  Caeliac , and  the 
Superior  and  Inferior  Mcfenterics ; ail  of  which  ai e Azjgous  or 
fingle  Arteries  afifing  from  the  fore  part  of  the  Aorta. 

Arteria  Coeliaca. 

The  Arteria  Coeliaca,  arifts  from  the  Aorta,  immedi- 
ately after  it  erht-iges  from  between  the  Crura  of  the  Diaphragm 
into  the  Abdomen  ; and  is  ftuated  at  the  upper  edge  of  lue  Pan- 
creas. 

The  Trunk  of  the  Coeliac  Artery  is  remaikably  fliort,  being 
little  more  than  half  an  inch  in  length,  before  it  divides  into  its 
three  prine  pai  Branches,  called  from  their  deftination,  Superior 
Gajh  ic,  Hepatic,  and  Splenic. 


201 


The  Gastrica  Superior,  or  Coronaria  Ventriculi 
Superior,  is  the  fmalleft  of  the  three.  It  goes  upwards,  and 
a little  towards  the  left,  to  reach  the  right  fide  of  the  upper  Ori- 
fice cf  the  Stomach. 

Here  it  fends  Branches  to  the  Cardia,  which  encircle  it,  and 
afcending  fomeway  upon  the  Efophagus,  communicate  with  the 
Arteriae  Efophageae. 

The  Trunk  of  the  Artery  afterwards  divides  upon  the  fmall 
Curvature  of  the  Stomach,  into  principal  Branches,  fome  of 
which  run  acrofs  the  upper  and  under  Surfaces,  and  others  ob- 
liquely towards  the  right  fide;  fupplying  a large  portion  of  the 
Stomach,  and  fending  Twigs  to  the  Omentum  Minus, — while 
the  Trunk  is  frequently  extended  as  far  as  the  Pylorus. 

The  Arteria  Hepatica,  the  largeft  of  the  three,  pafi'es  ob- 
liquely upwards,  towards  the  Pylorus, — before,  and  a litttle  to 
the  right  tide  cf  the  Lob-ulus  Spigelii, — till  it  arrives  at  the  Ca- 
vity of  the  Liver  called  Porta. 

Where  it  approaches  the  Porta,  it  divides  into  the  Gaftroica- 
Inferior  Dextra,  and  the  Proper  Hepatic  Artery. 

The  Gastrica  Dextra,  or  Gastrica  Inferior  Dex- 
tra, or  Gastro-Epiploica  Dextra,  feuds  out — 

The  Arteria  Pylorica.  which,  however,  is  frequently  produced 
immediately  from  the  Hepatic  Artery.  It  gives  Branches  to  the 
Pylorus  and  other  parts  about  t:ie  final!  end  of  the  Stomach,  and 
afterwards  runs  fome  way  along  its  fmail  Curvature,  incfcuia- 
ting  with  the  Sjpetior  Gaftric  Artery. 

Befides  this  principal  Branch,  there  are  a few  fmailer  ones  fent 
from  the  Gaftrica  Inferior  to  the  Pylorus. 

The  Duodenalis,  whjch  is  difperled  upon  the  beginning  and 
right  portion  of  the  Duodenum,  along  with  other  Branches  com- 
ing from  the  fame  fource,  but  of  inferior  fize. 

Rami  Pancreatici,  diftributed  to  the  right  end  of  the  Pan- 
creas. 

After  furnifiiing  the  Branches  already  mentioned,  the  Inferi- 
or Gaftric  Artery  paffes  under  the  Pylorus  to  the  great  Curva- 
ture of  the  Stomach,  along  which  it  runs;  being  include.!,  to 
near  its  large  extremity,  in  the  Layers  of  the  Anterior  Portion  of 
the  Omentum. 

In  this  courfe,  it  fends  off— 

The  Rami  Epiploici,  which  are  long  and  /lender  Branches  dif- 
perfed  upon  the  Epiploon  or  Omentum. 

The  Rami  Gajirici,  which  plun  ing  fuddenly  into  both  fides 
of  the  Stomach,  communicate  with  the  Pyloric  and  Superior 
Gaftric  Arteries. 

The  Hepatic  Artery,  having  given  out  the  Inferior  Gaftric, 
and  frequently,  the  Pyloric  Artery,  foon  divides  into  two  prin- 
cipal Branches,  a right  and  left,  of  unequal  fize,  which  ruu 


202 


into  the  Porta the  one,— tinder  the  Hepatic  Du£t,— to  fupply 
the  great,  aad  the  other  the  final  1 Lobe  of  the  Liver. 

From  the  Right  Branch,  before  it  plunges  into  the  Liver,  is 
fent  off  the  rirteria  Cyflica  afterwards  dividing  into  two /m  iller 
Branches,  termed  GemelU,  which  are  difperfed  upon  the  Gall- 
bladder. 

Frequently,  befides  the  Hepatic  Artery  fent  of  from  the  Coe- 
] i ac,  there  is  another,  corning  fomesimes  fr,.m  the  Superior 
Gaftr'c,  at  other  times  from  the  Superior  Mefenteric  Ateiy,  to 
be  lent  into  the  Liver.  In  fuch  cafes,  the  Trunk  which  gives 
origin  to  this  additional  Arteiy  is  greater  than  ufual,  and.th« 
Hepatic  Branch  which  it  a companies  is  proportionally  imaller. 

The  Ar.ter.ia  Splenica,  nearly  equal  in  fize  to  the  Trunk 
of  the  Hepatica,  takes  a long  and  ferpentine  courfe  acrofs  t he 
left  fide  of  the  Body  ; running  firlt  behind,  then  at  the  tipper 
part  of  the  Pancreas  in  its  way  to  the  Spleen.  Its  Blanches 
are, 

The  Rami  Pancreatici,  which  are  few  in  number  and  fmail. 
They  run  from  the  Splenic  Artery  nearly  at  right  angels,  and 
fupply  the  greater  part  of  the  Pancreas. 

The  Gaftrica  Sinifra,  Gaflrica  Inferior  Sinifra,  or  Gaflro - 
Epiploica  Sinifra , which  is  conliderably  inferior  in  length  and 
fize  to  the  Gaftrica  Dextrit.  It  communicates  by  its  Brandies 
with  the  Gaftrica  Superior,  and  Inferior,  while  its  Trunk  runs  a 
little  way  towards  the  right  fide  along  the  great  Curvature  of  the 
Stomach. 

It  fends  feme  Rami  Pancreatici,  and  Gaflro -Epiploici,  and 
Mefo-colici  Siniftri,  to  the  Pancreas,  left;  portions  of  the  Omen- 
tum and  Mefocolon  ; while  its  Tiunk  frequently  forms  a com- 
mon Arch  with  the  Gaftrica  Dextra. 

Three  or  four  confiderab  e Branches,  termed  Eafa  Previa,  or 
drterice  Breves,  which  run  to  the  left  pari  of  the  great  Curva- 
ture of  the  Stomach,  to  be  diltributed  upon  its  large  extremity  ; 
their  Ramifications  anaftomuling  with  thofe  of  the  Superior  and 
of  the  Left  Inferior  Gaftric  Arteries. 

The  Rami  Splenici,  feveral  in  number  and  of  confiderable 
fize,  which  go  at  the  concave  fide  of  the  Spleen,  to  be  diftributed 
throughout  the  whole  of  its  fubftance. 

Mesenter.ica  Superior. 

The  Mesenterica  Superior  arifes  from  the  Aorta,  im- 
mediately below  the  Cceliac  Artery,  which  it  equals  in  fize  ; and 
running  under  the  Pancreas,  and  then  over  the  Duodenum,  it 
palfes  between  the  Layers  of  the  Mefentery  towards  the  under 
fide  of  the  Abdomen. 

In  its  defeent,  it  is  bent  a little  to  the  left  fide,  its  lower  ex- 
tremity nuning  towards  the  beginning  of  the  Colon. 

From  the  conyex  fide  of  the  Artery,  many  large  Branches  are  - 
fent  off  to  thefmall  Inteftines  ; while  others  proceed  in  the  oppo- 
fite  direftion  to  the  right  fide  of  the  Colon. 


203 


The  FirJ}  Arteries  Tent  off  from  the  Trunk  are  very  inconfide- 
rabie,  running  to  the  Pancieas  and  to  the  left  portion  of  the  Du- 
odenu  ii,  and  commun  casing  there  with  Branches  of  the  Coeliac 
Aitery. 

The  principal  Branches  from  the  left  ftde  of  the  Trunk  are 
difpetfed  upon  the  Jejunum  and  Ilium,  fupplying,  in  t heir courfe, 
the  Layers  of  the  Mefcntcry  with  the  parts  it  contains. 

The  firft  of  thefe  Branches  are  (hurt  and  fmail,  thole  which 
fucceed  gradually  increafe  in  length  and  lize  to  the  middle  of  the 
Arch,  after  which  they  dimimlh  aga  n fo  ewhat  in  the  fame  pro- 
portion towards  the  lower  part  of  the  Ilium. 

In  their  courfe  through  tne  Mefentery,  .he  principal  Branch- 
es communicate,  full  by  reciprocal  Arches,  then  by  Areolae  of 
different  figures,  which  inereafe  in  number,  but  diminifh  in  fize 
as  they  approach  the  Inteftines. 

From  thefe  Areolae,  many  Branches  are  detached,  which  take 
a ftraight  courfe  to  the  Inteftines,  and  are  afterwards  ramified 
through  their  fubftance,  forming  numbsrlefs  Analfomofes  with 
each  other. 

The  Branches  produced  from  the  right  or  concave  fide  of  the 
Trunk  are  iituaied  between  the  Layers  of  the  Melo-colon, — 
their  length  being  almoft  equal  to  the  breadth  of  that  Membrane. 

Near  the  Inteftines,  they  communicate  by  large  and  then  by 
fmaller  Arches  : Thefe  laft,  however,  are  lefs  frequent  than  thofe 
which  belong  to  the  fmail  Inteftines. 

The  principal  Branches  are  the  following: — 

The  lleo-colica,  which  arifes  near  the  tinder  part  of  the  Trunk, 
fupplies  the  end  of  the  Ilium  and  beginning  of  the  Colon,  and 
communicates  with  the  Branches  lent  from  the  extremity  of  the 
Trunk  of  the  Artery. 

A Short  Trunk,  which  divides  into— 

The  Colica  Dextra,  for  fupplying  the  right  fide  of  the  Colon, 
—its  Branches  communicating  with  thofe  of  the  lleo-colica  : And 

The  Colica-Media,  or  Media  Anajlomotica,  which  proceeds  to 
the  great  Aich  of  the  Colon. 

Near  the  Colon,  the  Colica  Media  divides  into  two  large 
Branches  ; one  forming  an  Ar.  h with  the  Dextra,  the  other  with 
a Branch  of  the  Mefenterica  Inferior. 

From  the  oppofue  fi  le  of  the  Colon,  Branches  of  this  Artery 
run  to  the  Omentum,  and  communicate  with  the  Gaftro-Epipioic 
Arteries. 

Befides  the  Colic  Branches  already  deferibed,  there  is  frequent- 
ly an  additional  one,  which  arifes  from  the  beginning  of  the  Su- 
perior Mefenteric  Artery,  and  in  its  afeent  fplits  into  two  others, 
one  of  which,  uniting  whh  ehe  Colica  Media,  forms  the  large 
Mefocolic  Arch,  and  the  other  a fimilar  Arch  with  the  afeending 
Branch  of  the  Inferior  Mefenteric  Artery. 


204 


Mesenterica  Inferior. 

The  Mesenterica  Inferior  arifes  from  the  Aorta  fome- 
■what  lower  than  half  way  between  the  Superior  Mefenteric  and 
the  Bifurcation  of  the  Aorta. 

It  defcends  obliquely  upon  the  left  Pfoas  Mufcle,  and  foon 
divides  into  principal  Branches. 

Thefe  near  the  Inteftine  join  with  each  other,  and  form  Arches, 
from  which  others  go  off  compoling  Areolae  in  fomefmeafure  fi- 
milar  to  thofe  which  belong  to  the  right  fide  of  the  Colon. — The 
principal  Branches  are  : — 

The  Ramus  Afcendens , which  divides  near  the  Intelline,  into 
two  Branches  ; one  of  which  joins  the  Colica  Media,  to  form 
the  great  Mefocoiic  Arch,  the  other  is  reflefled  upon  the  left 
portion  of  the  Colon. 

The  Colica  Siniftra,  which  is  frequently  double  from  its  ori- 
gin, or  at  other  times  lplitting  intwo  two  Branches,  one  joining 
the  Ramus  Afcendens,  the  other  palling  down  by  the  Sigmoid 
Flexure  of  the  Colon. 

The  Hemorrhoidalis  Interna , which  is  the  Trunk  continued. 
It  anaftomoles  with  the  Colica  Siniftra,  and  afterwards  defcends 
upon  the  back-part  of  the  Reftum  to  near  its  under  extremity. 

Veins. 

The  Veins  which  return  the  Blood  from  the  Chylopoetic  and 
Affiftant  Chylopoetic  Vifcera,  accompany  their  refpeffive  Arte- 
ries,—the  Hepatic  Branch  excepted. — They  have,  like  their  Ar- 
teries, large  and  frequent  Communications  with  each  other,  are 
much  fuperior  in  fize,  and,  as  well  as  the  other  Veins  of  the  Vil- 
cera  fituated  in  the  great  Cavities,  are  deftitute  of  Valves. 

The  following  are  the  Principal  Trunks. 

The  Mesenterica,  or  Mesaraica  Minor,  or  II/c- 

MORRKOIDALIS  INTERNA. 

The  Mesenterica  Minor,  running  up  at  the  left  fide  of 
the  Spine,  receives— 

The  Proper  Vena  Hemorrhoidalis  Interna,  which 
returns  the  Blood  from  the  Inteftinum  Reftum  ; — the  name  ob- 
tained from  the  Vein  being  fuppofed  to  be  connected  with  the 
Tumours  called  Hemorrhoids  or  Piles. 

The  Vena  Colica  Siniftra,  which  return  the  Blood  from  the 
left  portion  or  fide  of  the  Colon. 

A Vena  Duodenalis,  which  returns  the  Blood  from  the  left 
portion  of  the  Duodenum. 

The  Mefenteiica  Minor  commonly  terminates  in  the  Vena 
Splenica,  though  not  unfrequently  in  the  Mefenteriea  Superior. 

Vena  Splenica. — The  Vena  Splenica,  fituated  at  the  under 
fide  of  its  Artery  and  immediately  behind  the  Pancreas,  re- 
ceives— 


205 


The  Rami  Splenici,  which  return  the  Blood  from  the  Spleen  : 
The  Rami  Pancreatici,  which  pafs  from  the  under  end  of  the 
Pancreas  : 

The  Vena  Breves,  or  Vafta  Bre-via,  which  come  from  the  left 
or  great  end  of  the  Stomach  : 

The  Vena  Gaftrica  Siniftra,  or  Epiploica  SiniBra,  which  comes 
from  part  of, the  great  Arch  of  the  Stomach,  and  correfponding 
portion  of  the  Omentum  : 

The  Gaftrica  Superior,  which  comes  from  the  fmall  Curva- 
ture of  the  Stomach  and  Omentum  Minus,  and  goes  into  the 
Splenic  near  its  termination,  or  into  the  beginning  of  the  Vena 
Portae.  . . 

The  Splenic  and  Inferior  Mefenteric  Veins,  after  receiving 
their  refpeftive  Branches,  form  a lhort  Trunk  which  joins  the 
Superior  Mefenteric. 

Vena  Me  s enteric  a Superior,  or  Major.  The  Great 
Mefenteric  Veiif,  fituated  at  the  under  fide  of  the  Artery,  re- 
ceives— s 

The  Rami  Mefenterici,  which  are  very  large  and  numerous,  re- 
turning the  Blood  from  the  Jejunum  and  Ilium, — the  Branches 
going  into  the  left  fide  of  the  general  Trunk. 

The  lleo-Colica,  which  comes  from  the  end  of  the  Ilium  and 
beginning  of  the  Colon. 

The  Colica  Dextra,  which  belongs  to  the  right  fide  of  the  Co. 
Ion,  and  terminates  in  the  right  or  concave  fide  of  the  Mefenteric 
Trunk. 

The  Colica  Media  Anaftomotica,  which  comes  from  the  right 
portion  of  the  Great  Arch  of  the  Colon,  forming,  with  the  de- 
fcending  Branch  of  the  Mefenterica  Minor,  a large  Arch  fimilar 
to  that  of  the  correfponding  Artery,  and  terminating  alfo  in  the 
right  fide  of  the  Trunk. 

The  Gaftro  - Epiploica  Dextra,  which  belongs  to  the  right  por- 
tions of  the  Stomach  and  Omentum,  and  frequently  unites  with 
the  Veins  from  the  fide  of  the  Colon,  forming  a fhort  common 
Trunk,  which  has  the  term  of  Gaftro-Colica  applied  to  it. 

The  Pylorica  and  Duodenalis,  which  fometimes  terminate 
in  the  Superior  Mefenteric,  at  othertimes  in  the  Gaftrica  Dextra. 

The  Great  Mefenteric  Vein,  formed  by  the  Branches  mention- 
el  above,  paffes  over  the  beginning  of  the  correfponding  Artery, 
and  joins  the  Vena  Splenica. 

The  Trunk  formed  by  thefe  Veins,  runs  under  the' head  of 
the  Pancreas,  and  here  obtains  the  name  of  Vena.  Port ee,  or  V. 
Portarufn. 

Vena  Port/e. 

The  Vena  Port.s,  formed  by  the  two  Mefenteries,  and  by 
the  Splenic  Vein,  returns  the  Blood  from  the  Stomach  and  Intef- 
tines,  and  from  the  Spleen,  Pancreas,  and  Omenta, 

Vol.  II.  S 


206 


The  under  part  of  the  Vena  Portae  is  termed  by  fome  Authors 
Vena  Porta’  Abdominalis,  or  Vent  rails  ; while  the  upper  part, — 
being-  of  great  fize,  but  without  having  any  particular  Dilatation 
in  it, — is  called  Sinus  of  the  Vena  Portae. 

The  Vena  Portae,  af  its  beginning,  frequently  receives  the  Ve- 
r.a  Gaftrica  Dextra,  the  Gaftrica  Superior,  the  Pylorica,  and  the 
Duodenalis,  which  at  oilier  times  terminate  in  one  of  the  great 
Trunks  which  form  it. 

It  pafies  upwards,  inclining  a little  to  the  right  in  its  courfe  to 
the  Liver,  having  the  Trunks  of  the  Biliary  Duffs  before,  and 
the  Hepatic  Artery  on  the  left  fide  of  it, — and  is  about  three  or 
four  inches  in  length. 

When  it  reaches  the  Porta  of  the  Liver,  it  receives  the  Venae 
Cyfticae  into  its  Trunk,  or  into  its  right  divifion,  either  by  two 
feparate  Branches,  or  tiiefe  united  into  a fmgle  Vein. 

In  the  Porta,  it  divides  into  two  great  Branches,  a right  and 
left,  fometimes  termed  Vena  Porta  Hepatica,  which  go  off  nearly 
at  right  angles,  to  be  difpcrl’ed,  through  the  fubffance  of  the  li- 
ver, after  the  manner  of  an  Artery,  the  fuborclinate  Branches  ac- 
companying thofe  of  the  A.  Hepatica. 

From  the  extremities  of  the  Vena  Portarum,  and  likewile  from 
the  extremities  of  the  Hepatic  Artery,  a fet  of  Veins  arife,  term- 
ed Vena  Hepatica,  and  fometimes  Vena  Cava  Iiepatica,  which 
accompany  the  Branches  of  the  Hepatic  Arteiy  and  Vena  Por- 
tarum. 

The  Branches  of  the  Veil*  Hepaticas  afterwards  unite  into 
large  Trunks,  which  recede  from  the  Hepatic  Artery  and  Vena 
Portae,  and  terminate  in  the  Inferior  Cava. 

Their  termination  in  the  Cava  is  by  two,  and  frequently  by 
three  Trunks,  at  the  place  where  it  perforates  the  Diaphragm  ; 
but  commonly,  below  this,  a few  final  1 Hepatic  Branches-go  into 
the  Cava  where  it  is  fituated  behind  the  Liver. 


BLOOD-VESSELS  of  the  OPvGANS  of  URINE  and 
GENERATION. 

Arteria  Renalis.  The  Arteria  Renalis,  called  alfo  A. 
Emulgens,  arifes  from  the  fide  of  the  Aorta,  a little  below  the  root 
©f  the  Superior  Mefenteric  Artery. 

It  commonly  comes  off  by  one  large  Trunk,  though  frequent- 
ly by  two  or  more,  in  which  cafe,  each  of  thefe  is  1'maUer  than 
when  the  Artery  is  fingle. 

It  runs  acrofs  the  Spine  and  Pfoas  Mufcle,  nearly  in  a tranf- 
*c,fe  direction.  The  Artery  of  the  right  fide  goes  behind  the 


207 


Vena  Cava,  and  is  longer  than  the  left,  in  confeqnence  of  the 
Cava  being  fuuated  between  the  Aorta  and  the  Right  Kidney. 

At  the  concave  edge  of  the  Kidney,  the  Artery  divides  into 
three  or  four  Branches,  which  fometimes  fend  Twigs  to  the 
GlandulaRenslis  and  Tunica  Adipcfa  of  the  Kidney. 

Ti;e  Renal  Branches  then  plunge  into  the  l'ubftahce  of  the  Kid- 
ney, furround  its  Pelvis,  and  afterwards  ramify  chiefly  in  its 
Conical  Subftance  ; — forming  Arches  with  each  other,  but  few 
in  number,  at  the  roots  of  the  Papillae. 

The  Vena  RenaHS,  or  Emulgens,  terminates  in  the  In- 
ferior Cava;  and  is  more  fuperncial  than  its  correfponding  Arte- 
ry. It  is  the  largelf  Vein  received  by  the  Cava  from  its  origin 
to  the  part  where  it  reaches  the  Liver. 

The  left  Renal  Vein-  is  the  longer  of  the  two  ; — the  Aorta,  be- 
fore which  it  paffes,  being  lltuated  between  the  Cava  and  Left 
Kidney. 

Arteri*  Capsularss.  The  Arteriae  Capfulares,  or  Ar- 
teries of  the  Renal  Gap  Jules  or  Glands,  are  final  1 but  numerous. 

They  are  derived  from  the  Renal  and  Diaphragmatic  Arteries  ; 
and,  in  general,  the  left  Renal  Gland  receives  additional 
Branches  from  the  Trunk  of  the  Aorta. 

The  Ven^e  Capsulaues  commonly  unite  into  a largeTrunk, 
which,  in  the  left  fide,  terminates  in  that  of  the  Kidney,  while 
in  the  right  it  frequently  goes  into  the  Cava. 

Arteri/E  Adipose.  The  Arteres  which  Amply  the  Tu- 
nica Adipofa  of  the  Kidney  are  numerous  Twigs  proceeding 
from  the  Diaphragmatic,  Capfular,  and  Renal  Arteries,  or  frora 
others  near  it. 

The  Veins  which  return  from  the  extremities  of  thefe  Arteries 
pafs  into  the  Trunks  adjacent. 

Arteria  S-permatiCA.  The  Spermatic  Artery,  the  diame- 
ter of  which  iifmall  when  compared  with  its  great  lengih,  arifes 
oppolite  to  it*  fellow,  from  the  fore-part -of  the  Aorta,  a little 
below  the  Renal  Arteries. 

Sometimes  it  anfes  from  the  A.  Renalis,  at  other  times  a little 
higher  from  the  Aorta,  and  in  rarer  inftances  from  the  Diaphrag- 
matic Artery. 

It  delcends,  in  a waving  direction,  on  the  furface  of  the  Pfoas 
Mufcle,  covered  by  the  Peritoneum  ; the  right  palling  obliquely 
over  the  Cava,  the  left  behind  the  Colic  Arteries  of  the  fame 
fide,  and  both  before  the  Ureters  to  the  under  part  of  the  Abdo- 
men. 

After  this,  it  perforates  the  R'ng  of  the  Obliquus  Externusr 
and  runs  in  the  Spermatic  Cord,  where  it  divides  into  Branches 
which  are  difperfed  in  a very  convoluted  manner  upon  the  Telticle 
and  Epididymis. 

In  the  defeent  of  the  Artery  it  imparts — 

livigs  to  the  Tunica  Adipofa  of  the  Kidney. 

To  the  Peritoneum  and"Ce!iular  Subftance  near  it;— and 


20S 


To  the  Ureters, — which  are  alfo  fupplied  with  other  Arteries 
from  the  adjacent.  Vefiels,  viz.  from  the  Rena]  and  Capfular  Ar- 
teries, from  the  Aorta,  the  Iliacae_and  Veilcales. 

The  Ven  a Spe RM atic a is  much  larger  than  its  correfpon- 
ding  Artery,  and  is  furnifhed  with  Valves  within,  but  more  par- 
ticularly without  the  Abdomen. 

It  forms  a Plexus  which  accompanies  the  Artery,  and  about 
the  place  where  it  recedes  from  it,  which  is  nearly  oppofite  the 
under  end  of  the  Kidney,  it  forms  a fingle  Trunk,  which  in  the 
right  fide  goes  into  the  Cava  a little  below  the  Emulgent  Vein, 
and  in  the  left  into  the  correfponding  Vena  Renalis. 

Beiides  the  Artery  commonly  termed  Spermatic,  the  Tefticle 
generally  receives  a Minute  Branch,  which  arifesfrom  the  Hypo- 
gaftric,  and  accompanies  the  Vas  Deferens  to  the  Body  of  the 
Tefticle  upon  which  it  is  difperfed, — communicating  there  with 
the  Branches  of  the  Spermatic  Artery. 

The  Vein  proper  to  this  Artery,  terminates  in  the  Vena  Hypo- 
gaftrica. 

The  Spermatic  Artery,  in  the  Female,  has  the  fame  kind  of 
Origin,  and  the  fame  courfe  through  the  Abdomen  as  in  the 
Male  but  in  place  of  perforating  the  Abdominal  Ring,  as  it 
does  in  the  latter,  it  defcends  into  the  Pelvis,  between  the  Lamina 
of  the  Ligamentum  Latum,  to  be  difperfed  firft  upon  the  Ova- 
rium and  Uterine  Tube,  and  then  upon  the  Body  of  the  Uterus 
itfelf, — pafling  in  at  its  corner,  and  communicating  with  the  Ar- 
tery of  the  oppofite  fide. 

The  Spermatic  Vein  has  the  fame  termination  in  the  Female  as 
in  the  Male, — but  is  confiderably  larger. 

Arteri^  IliaCjE.  The  Iliac  Arteries  confift  of  the  T<wo 
Common  lliacs,  which  are  formed  by  the  Bifurcation  of  the  Aor- 
ta ; and  of  the  External  and  Internal  lliacs  of  each  fide,  which 
are  formed  by  the  Bifurcation  of  the  Iliacas  Communes. 

The  External  Iliac  paffes  out  of  the  Abdomen  behind  the  Li- 
gament of  I'oupart  ; the  Internal,  termed  alfo  A.  HypogaJIrica, 
defcends  obliquely  into  the  Pelvis. 

At  tjie  fide  of  the  Pelvis,  the  Internal  divides  into  many 
Branches,  feme  of  which  belong  to  the  Organs  of  Urine  and  Ge- 
neiation,  the  reft  to  other  parts  of  tk^Pelvis  and  adjacent  parts 
of  the  Thigh. 

The  following  are  the  Branches  lent  from  the  Hypogaftric  Ar- 
tery to  the  Organs  of  Urine  and  Generation. 

Arteria  Umbilicalis.  The  Arteria  Umbilicalis  appears 
in  the  Foetus,  as  the  continued  Trunk  of  the  IptotnaL  Iliac  ; but 
in  the  Adult,  is  fliri veiled  in  the  form  cf  a Ligament,  excepting 
at  its  beginning  or  under  part. 

The  beginning  of  the  Umbilical  Artery  gives  off — 

One  or  more  Arteries  Vejicales,  which  run  to  the  ru  der  part  of 
the  Bladder,  and  extend  along  its  Tides  as  far  as  the  Fundus  Ve- 


209 


ficae.  At  their  origin,  they  furnifh  Twigs  to  the  Veficulae  Semi- 
i.ales,  Proftate  Gland,  and  Reftum. 

In  the  Female,  the  Umbilical  Artery  fends  minute  Branches  to 
the  Uterus  and  Vagina. 

Arteria  Uterina.  The  Arteria  Uterina,  termed  alfo  Ute- 
rina Hypogajlrica,  is  much  larger  than  the  Spermatic  Artery. 

It  arifes  from  the  Hypogaftric,  near  the  origin  of  the  A.  Pu- 
dica,  and  runs  into  the  Uterus  at  its  under  extremity. 

It  is  afterwards  reflefted  upwards  along  the  edge  of  the  Uterus, 
towards  its  Fundus  or  upper  part,  where  it  meets  with  the  Sper- 
matic Artery,  with  which  it  forms  frequent  Anaftomoles,  and 
afterwards  many  Communications  with  the  Uterine  Artery  of 
the  oppofite  fide. 

The  Uterine  Artery  fends  Branches  downwards  to  the  fub- 
ftance  of  the  Vagina,  and  others  forwards  to  be  dil'perfed  upon 
the  Bladder. 

Arteria  Vaginalis.  The  Arteria  Vaginalis  is  frequently 
awanting.— When  prefent,  it  arifes  from  foine  of  the  Branches 
of  the  Hypogaftric,— as  that  common  to  the  Ifchi  die  and  Pu- 
dic, — or  from  the  Haemorrhoidalis  Media  j and  is  diftributed 
upon  the  under  part  of  the  Vagina. 

Befides  this,  there  are  other  Vaginal  Branches  from  the  neigh- 
bouring Arteries  ; as  from  the  Veficales , Uterina , and  Pudica, 
which  communicate  with  each  other,  and  with  the  proper  Vagina- 
lis, upon  the  fubftance  of  the  Vagina. 

Arteria  Pudica,  or  Pudenda  Communis. — The  Arte- 
ria Pudica,  named  from  its  belonging  to  the  Parts  of  Generation 
in  both  fexes,  comes  off  either  immediately  from  the  Trunk  of 
the  Hypogaftric,  or  from  the  A.  Ilchiatica. 

' It  palfes  out  of  the  Pelvis,  through  the  under  part  of  the 
Notch  of  the  Os  Ilium,  at  the  lower  edge  of  the  Pyriform  Muf- 
cle. 

It  then  turns  between  the  Sacro-fciatic  Ligaments,  to  get  to 
the  inner  fide  of  the  Tuber  Ifchii,  where  it  is  lodged  deep  in  the 
Cellular  Subftance. 

From  the  Tuber,  it  proceeds  along  the  inner  fide  of  the  Crus 
of  the  Os  Ifchium  and  of  the  Os  Pubis,  and  behind  the  Crus  of 
the'Penis,  till  it  approaches  the  Symphyfis  of  thePubis. 

In  it s courfe,  it  fends  off  many  Branches,  of  which  the  follow- 
ing are  the  principal,  viz. — 

Branches  to  the  Veficulae  Seminaies,  Proftate  Gland,  Neck  of 
the  Bladder,  andRe£tum. 

_ Branches  to  the  Mufcles  and  parts  adjacent  to  the  Sacro  fcia- 
t’c  ^jgaments  5 fome  of  them  extending  as  far  as  the  Joint  of 
the  Thigh-bone. 

Branches  to  the  Mufcles,  Membranes,  and  Fat  about  the  Tu- 
ber of  the  Os  Ifchium. 

Vol.  II.  S 2 


210 


The  Arteria  Hamorrhoidalis  Externa,  which  foon  divides  into 
Branches,  to  fupply  the  Mufcles  and  Integuments  about  the 
verge  of  the  Anus. 

The  A.  Perinei , which  paffes  under  the  Tranfverfalis  Perinci 
Mufcle,  in  the  fuace  between  the  Crus  of  the  Penis  and  Bulb  of 
the  Urethra,  and  gives  Branches  to  the  Skin  and  Mufcles  aftbe. 
fore-part  of  the  Anus  and  root  of  the  Penis,  and  to  the  Scro- 
tum ; while  the  Artery  itfelf  terminates  on  the  under  tide  of  the 
Penis. 

After  difperfing  the  Branches  already  mentioned,  the  Pudic 
Artery  divides,  at  the  root  of  the  Penis,  into  three  principal 
Branches,  viz. — 

The  Firji  Branch , which  paffes  into  the  Bulb  of  the  Urethra, 
and  is  continued  forwards  in  the  Corpus  Spongiofum  Urethrae, 
into  ;he  Cells  of  which  many  of  its  Branches  open. 

The  Second  Bi anch,  termed  Profunda  Penis,  which  goes  into 
the  Crus  Penis,  anddirefls  its  courfe  in  the  Corpus  Cnvernofum  ; 
its  Branches  communicating  with  the  Artery  of  the  oppofrte  fide, 
and  with  the  Cells  of  the  Penis. 

The  Third  Branch,  called  DorfaUs  Penis,  which  turns  be- 
tween the  Symphyfis  of  the  Pubis  and  root  of  the  Penis,  and  pro- 
ceeds along  the  Dorfum,  as  far  as  the  Gians,  adhering  clolely 
to  the  L’gamentous  Subftance  which  inclofes  the  Corpora  Caver- 
nofa,  and  fending  Branches  to  it  and  to  the  Integuments. 

In  the  Female,  the  Pudic  Artery  has  the  fame  general  courfe  as 
in  the  Male. 

After  reaching  the  inner  fide  of  the  Tuber  of  the  Os  Ifchium, 
it  is  extended  forwards,  and  fends  Branches  to  the  Anus,  Peri- 
neum, end  of  the  Vagina,  and  Labia  Externa,  and  terminates  in 
the  Clitoris,  tbmewhat  in  afimilar  manner  as  in  the  Penis. 

The  Blood  is  returned  from  the  Branches  of  the  Hypogaftt  ic 
Artery  difperfed  upon  the  Organs  ol  Urine  and  Generation,  by 
the  following  Veins,  viz.— 

The  Vena  Veficalis,  which  returns  the  Blood  from  the  Bladder., 

The  Vena  Uteri): a Hypogajirica , which  comes  from  the  Uterus. 

The  Vena  Magna  lpjius  Penis,  which  tuns  along  the  middle 
of  the  Dorfum,  and  is  often  double  to  near  the  root  of  the  Pe- 
nis ; after  which  it  paffes  between  this  and  the  Arch  of  the  Pu- 
bes, forming  a Plexus  which  furrounds  the  Neck  of  the  Bladder, 
and  fending  out  Branches  which  terminate  in  others  at  the  frdes 
of  this  Vifcus. 

The  Vena  Pudica,  which  communicates  anteriorly  with  the 
Branches  of  the  Vena  Magna  at  the  root  of  the  Penis,  and  after- 
wards paffes  back  with  the  correfponding  Artery. 

The  Vena  Eegtnentorum  Penis,  which  is  formed  by  fmall  Sub- 
cutaneous Branches,  and  ends  in  the  top  of  the  Femoral  Vein. 

The  Veins  above-mentioned,  the  1 a if  excepted,  terminate  in  the 
Hypogafhica,  along  with  other  Veins  belonging  to  the  Pelvis,  to 
be  afterwards  deferibed. 


211 


BLOOD-VESSELS  of  the  CONTAINING  PARTS  of 
THE  ABDOMEN,  AND  OF  THE  PELVIS  AND 
INFERIOR  EXTREMITY. 

Arteria:  Lumeares. — The  Lumbar  Arteries,  which  are 
commonly  four  in  number  on  each  fide,  arife  in  pairs  from  the 
back-part  of  the  Abdominal  Aorta,  in  the  fame  manner  as  the  In- 
tercoftals  do  from  the  Aorta  in  the  Thorax. 

They  run  fir  ft  over  the  fore-part  of  the  Bodies  of  the  four  up- 
permolt  Lumha-r  Vertebraae,  and  afterwards  go  between  them  and 
the  Pfoae  Mufcles,  in  their  way  towards  the  fides  of  the  Abdo- 
men. 

They  give  Branches  to  the  Spine,  to  the  Spinal  Marrow  and 
Its  '^vdembrhnes  ; are  particularly  difperfed  upon  the  Lumbar 
Mufcles,  and  upon  "{he ; Tranfverfus  and  Obliqui  Abdominis; 
and  perforating  thefe,  they  alfo  furnilh  Branches  to  the  large 
Mufcles  and  the  Integuments  in  the  back-part  of  the  Loins. 

Superiorly,  they  communicate  with  the  lower  Intercoftal  and 
Diaphragmatic  Arteries. 

Sacra  Media.  The  Sacra  Media  is  a fmall  Azygos  Ar- 
tery, which  aril’es  from  the  under  and  back-part  of  the  Aorta, 
immediately  at  its  Bifurcation. 

It  generally'  fends  off  a Branch  over  each  fide  of  the  laftYer- 
tebra  of  the  Loins,  which  takes  nearly  the  fame  courl’e  back- 
wards with  the  Arterise  Lurhbares. 

The  Sacral  Artery  afterwards  defeends  along  the  middle  of 
the  Sacrum,  as  far  as  the  Os  Ccccygis,  fending  Branches  to  the 
Membranes  and  Subftance  of  thefe  Bones,  and  to  the  back  part 
of  theReftum. 

Iliac.®  Communes.  After,  giving  off  the  Arteries  of  the 
Contents  and  of  the  containing  parts  of  the  Abdomen,  the 
Aorta,  upon  the  under  part  of  the  Fourth  Lumbar  Vertebra, 
divides  into  the  Two  Common  Iliac  Arteiies,  which  are  of  equal 
fize. 

They  pafs  obliquely  downwards  and  outwards  ; and  at  the  un- 
der and  lateral  parts  of  the  laft  Vertebra  of  the  Loins,  i.  e.  oppo- 
nte  to  the  polterior  Symphylas  of  the  Pelvis,  each  divides  into 
two  others,  an  Anterior,  termed  Iliaca  Extenia,  and  a Pofterior, 
termed  Iliaca  Interna,  or  Hypogaftrica. 

Iliaca  Externa.  The  Iliaca  Externa,  which  appears  in 
the  Adult  as  the  continuation  of  the  common  Trunk,  delcends 
along  the  Brim  of  the  Pelvis,  taking  a curved  dire&ioifby  the 
lide  of  the  Pfoas  Mufcle,  and  afterwards  paffes  behind  the  Liga- 
ment of  Poupart,  to  form  the  Femoral  Artery. 

In  this  couife,  it  does  not  fend  off  any  Branches,  excepting 
fometimes  a Twig  or  two  to  the  Peritoneum,  Pfoas  Mufcle,  &c. 


212 


till  it  is  about  to  leave  the  Abdomen,  where  it  gives  rife  to  two 
principal  Arteries, — the  Epigajfrica,  and  Circumflexa  OJJis  IHi. 

The  Arteria  Epigastrica,  obtaining  its  name  from  its 
fituation  in  the  fore-part  of  the  Belly,  goes  off  from  the  inner 
fide  of  the  Femoral  Artery,  immediately  before  that  Velfel  gets 
behind  the  Ligament  of  Poupart. 

At  its  origin,  it  is  a little  bent  downwards,  and  about  half  an 
inch  from  the  place  where  it  firft  comes  off,  it  crofles  obliquely 
upwards  and  inwards,  behind  the  Spermatic  Cord  in  the  Male, 
and  round  Ligament  in  the  Female. 

It  proceeds  in  this  oblique  manner  behind  the  Tendon  of  the 
Tranfverfus,  till  it  reaches  as  high  as  the  point  of  the  Pyramida- 
lis,  after  which  it  takes  a perpendicular  direflion  along  the  back- 
part  of  the  Rectus  Abdominis  Mufcle. 

It  furnilhes  Branches  to  the  Mufcles,  Integuments,. and  Mem- 
branes of  the  fore-part  of  the  Abdomen,  communicates  in  feve- 
ral  places  with  the  Lumbar  Arteries,  and  terminates  a little  above 
the  Umbilicus,  where  it  foims  feveral  diftinft  though  fmall 
Anaftomofes  with  the  under  end  of  the  Mammaria  Interna. 

Circumflexa  Ossis  Ilii. — The  CircumP»ex  Artery  of  the 
Ilium,  almoft  as  large  as  theEpigaftric  Artery,  ariles  nearly  op- 
pofite  to  it,  though  frequeutly  a little  lower, — immediately  be- 
hind the  under  end  of  the  Fallopian  Ligament. 

It  runs  at  the  under  edge  of  the  Os  Ilium,  till  it  arrives  near 
the  Vertebrate  of  the  Loins. 

It  gives  Branches  to  the  Pfoas  and  Iliac  Mufcles,  to  the  under 
end  of  the  Obliqui  and  Tranfverfus  Abdominis,  and  at  length 
communicites  with  the  Epigaftric,  and  with  the  Inferior  Arte- 
ries of  the  Loins. 

Iliaca  Interna.  The  Uiaca  Interna,  or  Hypogaftrica' 
palfes  downwards  and  backwards  in  the  pofterior  and  lateral  part 
of  the  Cavity  of  the  Pelvis,  for  about  a couple  of  Fingers- 
breadth,  after  which  it  generally  divides  into  a Pofterior  and  An- 
terior Set  of  Branches  ; the  former  fupplying  the  parts  neareft  the 
Sacrum  and  Ilium,  the  latter  belonging  more  immediately  to  the 
parts  about  the  Anterior  region  of  the  Pelvis. 

Posterior  Branches. 

Imo-L  umbar  is,  or  1 1 1 a c a Interna  Mitjor.  The  Ileo- 
lumbar  is  a fmall  Artery,  arifing  fometimes  from  the  end  of  the 
Hypogaftric,  at  other  times  from  the  beginning  of  the  Glutea. 

It  palfes  outwards  under  the  Pfoas  Mufcle,  and  divides  fud- 
denly  into  Blanches,  one  of  which  frequently  forms  a kind  of 
Lumbalis  Ima. 

The  other  Blanches  go  to  the  Pfoas,  and  Iliacus  Internus 
Mufcles,  communicating  there  wiih  the  Lumbar  Arteries  and 
Circumflex  Branches  of  the  Ilium; — a particular  Twigconftitu- 
ting  an  A.  Nutritia,  or  Medallaris  of  the  Os  Ilium. 


21.3 


SacR/e  Laterales.  Thefe  are  generally  two  or  three  in 
number,  arifing  from  the  common  Trunk,  or  frequently  from 
the  Gluteal  Artery  ; — though  fometimes,  there  is  only  a fingle 
Artery,  which  defcends  by  the  fides  of  the  Sacral  Holes,  giving 
Branches,  which  fupply  the  place  of  the  Sacrae  Laterales,  and 
fometimes  alfo  of  the  Sacra  Media. 

They  furnifh  Branches  to  the  Membranes  on  the  fur  face  of  the 
Os  Sacrum,  and  inofculate  by  crofs  Twigs  with  the  Sacra  Me- 
dia. 

Their  principal  Trunks  enter  the  Anterior  Sacral  Holes,  to 
be  diftributed  upon  the  Cauda  Equina  and  the  Membranes  and 
Bones  inclofing  it. 

Arteri  a Glut  ea. — This  is  fometimes  termed  Iliaca  Po- 
Jierior,  and  is  the  lsrgeft  Branch  of  the  Hypogaftnc  Artery. 

Soon  after  it  arifes,  it  pafies  through  the  upper  part  of  the 
great  Notch  of  the  Os  Ilium,  and  is  refle&ed  over  the  edge  of  the 
Bone,  in  the  manner  of  the  Inferior  Scapulary  Artery. 

At  the  under  edge  of  the  Gluteus  Medius,  it  is  divided  into 
two  fets  of  Branches,  one  of  which  runs  in  a radiated  direction 
clofe  upon  the  Bone,  and  is  chiefly  difperfed  upon  the  two  fmaller 
Glutei,  while  Branches  of  inferior  fize  run  fome  of  them  down- 
wards to  the  Mufcles  and  Ligaments  about  the  Joint  of  the 
Thigh,  and  others  backwards  to  the  parts  about  the  Sacrum, 
communicating  with  the  Lateral  Sacral  Arteries  through  the  Po- 
fterior  Foramina  of  the  Os  Sacrum. 

The  other  fct  of  Branches  of  the  Gluteal  Artery  creeps  in  be- 
tween the  Gluteous  Medius  and  Maximus  Mufcles,  upon  the 
latter  of  which  it  is  chiefly  difperfed. 

Anterior  Branches. 

Arteria  Obturatoria,  or  Oeturatrix.— ' The  Obturator 
Artery  has  its  origin  from  the  Trunk  of  the  Hvpogaftric,  or 
from  the  Ileo-lumbar  or  from  the  Ifchiatic,  and  fometimes  from 
the  end  of  the  Iliaca  Externa. 

It  defcends  in  the  Pelvis  by  the  fide  cf  the  Pfoas  Mufcle,  and 
afterwards  pafles  through  the  Hole  at  the  upper  part  of  the  Ob- 
turator Ligament. 

While  in  the  Pelvis,  it  frequently  gives  Twigs  to  the  Bladder 
and  other  parts  near  it. 

After  perforating  the  Ligament,  it  divides  into  Branches,  one 
fet  of  which  are  difperfed  upon  the  parts  about  the  Hip-joint, 
while  another  belong  to  the  Obturator  Mufcle,  and  to  the  Muf- 
cles which  are  fituated  at  the  upper  and  inner  part  of  the  Thigh, 
— the  two  fets  of  Branches  inofculating  with  each  other. 

Arteria  Umbilicalis. — The  Umbilical  Artery  fends  cff 
P,ami  Veficales  from  its  under  part  or  beginning  ; the  reft  of  it,  in 
the  Adult,  being  fnri veiled  into  Ligament,  as  already  obferved. 


214 


Vesicalis  Ima  of  Haller.—' This  is  a long  and  (lender 
Branch  which  frequently  comes  off  from  the  root  of  the  Pudica, 
and  runs  to  the  under  part  of  the  Bladder,  and  to  the  Prollate 
Gland. 

Arteria  Uterina.  The  Uterine  or  Uterine-Hypogaftric 
Artery,  is  difperfed  upon  the  Uterus,  as  has  been  already  tle- 
feribed. 

IliEMORRHoiDALis  Media.  The  middle  Kaemorrhcidal 
Artery  is  fometimes  fent  off  from  the  original  Trunk,  and  at 
other  times  from  fome  of  its  Branches,  as  the  Pudic  in  the  Male, 
or  Umbilical  in  the  Female. 

ft  is  chiefly  diftributea  upon  the  lower  end  of  the  Reftum, 
where  it  analtomofes  with  the  Hasmorrhoidalis  Interna.  It  fre- 
quently fends  Branches  to  the  under  part  of  the  Bladder,  to  the 
Veiiculae  Seminales  and  Proftate  in  the  Male;  and  to  the  Va- 
gina and  Bladder  in  the  Female. 

Pudica  Communis.—- The  Pudica  Communis,  termed  by 
fome  Authors  Htzmoi~rhoidalis  Externa,  belongs  to  the  parts  of 
Generation  and  Anus,  as  was  for  met  ly  taken  notice  of. 

Arteria  Sciatica.  The  Sciatic,  or  Ifchiatic  Artery  is  the 
largelt  of  the  Iliac  Branches,  the  Glutea  excepted. 

It  goes  through  the  under  part  of  the  Sciatic  Notch,  accom- 
panied by  the  Nerve  of  that  name  having  the  Pyriform  Mufcle 
between  it  and  the  Gluteal  Artery. 

It  afterwards  defccnds  fomeway  down  the  Thigh,  in  compa- 
ny with  tite  Scialic  Nerve,  in  the  hollow  between  the  great  Tro- 
chanter of  the  Thigh  bone  and  Tuber  of  the  Ifchium, — covered 
by  the  Gluteus  Maximus  Mufcle. 

It  fends  an  Artery  backwards,  termed  A.  Coccygea,  which 
creeps  along  the  Sacro- Sciatic  Ligaments,  furnifhing  Branches  to 
the  parts  about  the  Os  Coccygis,  and  others  which  afeend  from 
it,  and  anaftomofe  with  fome  of  the  lateral  Sacral  Arteries 
through  the  Holes  in  the  back-part  of  the  Os  Sacrum. 

The  principal  Branches  of  the  Sciatic  Artery,  however,  are 
difperfed  upon  the* under  part  of  the  Gluten s “Maximus  Mufcle, 
and  upon  tiiofe  at  the  upper  and  back-part  of  the  Thigh,  where 
they  communicate  with  the  Obturator  and  Pudic  Arteries. 

Arteria  Femoralis. 

The  Femoral  or  Crural  Artery, — the  continuation  of 
the  External  Iliac, — pafl'es  out  of  the  Abdcmen  between  the  Li- 
gament of  Poupart  and  Brim  of  the  Pelvis. 

At  its  firfl  exit,  it  is  funated  fuperficially  over  the  Ball  of  the 
Os  Ftmoris,  having  the  Flexors  of  the  Thigh  between  it  and  the 
joint. 

Farther  down,  it  is  lodged  deep  in  a hollow  at  the  upper  and 
inner  part  of  the  Thigh,  having  the  Reflus  and  Sartorius  upon 
the  outer,  and  the  Adduftores  Femoris  upon  the  inner  fide  of  it. 


215 


Here,  it  is  covered  by  the  Glands  of  the  Groin,  and  by  the 
general  Aponeurolis  and  Fst  ; and  from  this  part  it  defcends  at 
the  in  ide  of  the 'Thigh  turning  gradually  backwards  till  it  reach- 
es the  Ham. 

From  the  top  cf  the  Femoral  Artery,  a few  fmall  Branches  are 
fent  off  to  the  Superficial  Mufcles  and  Inguinal  Glands,  and  to 
the  common  Integuments  at  the  upper  part  of  the  Thigh  ; alfo 
one  or  two  others  termed  Pudic#  Extern#,  to  the  External  Parts 
of  Generation  and  Integuments  of  the  infide  of  the  Thigh. 

About  two  Fingers-bread'  h below  the  Ligament  of  Poupart, 
the  Femoral  Artery  divides,  fomewhat  like  the  Common  Iliac, 
into  Anterior  and  Poftenor  parts  : — The  former  is  the  Femoral 
Artery  lhiftly  lb  called,  the  latter  is  termed  Profunda  Femoris. 

Profunda  Femoris. 

The  Arterta  Profunda,  alfo  called  Vasta,  Posterior,  or 
Muscularis  Femoris,  immediately  at  its  origin  from  the  Fe- 
moral Artery,  gives  off  two  large  Branches, — the  Circumflex  a ln- 
terna,zx\<\  Cicumflexa  Externa , — which  run  in  oppofite  directions 
at  the  upper  part  of  the  Thigh. 

The  Circumflexa  Interna,  though  moft  frequently  com- 
ing off  from  the  beginning  of  the  Profunda,  often  arifes  higher 
than  it,  from  the  top  of  the  Femoral  ; and  there  are  now  and 
then  two  of  them,  one  a little  lower  than  the  other. 

It  paffes  between  the  under  end  of  the  Pfoas,  and  the  Peftina- 
lis  Mufcle,  and  afterwards  turns  round  the  inner  part  of  the 
Joint  of  the  Thigh. 

It  fends  off — 

Large  Branches  to  that  portion  of  the  Adduftor  Mufcles 
■which  belongs  to  the  upper  part  of  the  Thigh. 

Small  Branches  to  the  Mufcles  in  the  vicinity  of  the  Trochan- 
ters. 

A Branch,  termed  Articularis  Acetakulia  to  the  Capfular  Liga- 
ment of  the  Joint. 

A Twig,  which  enters  the  breach  at  the  underand  foie  part  of 
the  Acetabulum,  to  he  difperfed  upon  the  Ligamentum  Rotun- 
dum  and  the  fubdance  called  Gland  of  the  Joint. 

A confiderable  Branch,  which  analtomofes  with  the  Trunk  of 
the  Obturator  Artery  And 

Smaller  Branches  which  communicate  with  the  Arteria  Sci- 
atica- 

Circumflexa  Externa. — The  Circumflexa  Externa  arifes 
for  the  molt  part  nearly  oppofite  the  former,  but  frequently  a 
little  lower. — Nowand  then  this  artery  has  a double  Origin,  one 
of  the  Trunks  coming  off  higher  than  the  other. 

It  paffes  outwards  between  the  upper  ends  of  the  Refills,  Ten- 
for  Vagins  Femoris,  and  Vaftus  Externus  Mufcles,  and  over  the 
Great  Trochanter  of  the  Os  Femoirs. 


216 


It  fends  Branches  upwards  to  the  under  part  of  the  Glutei  and 
to  other  Mufcles  placed  at  the  inferior  and  back  part  of  the  Pel- 
vis, which  anallomofe  with  thofe  running  down  from  the  Arte- 
ria  Sciatica. 

Others  which  have  more  of  a lateral  dire&ion,  and  are  diftri- 
buted  upon  the  Mufcles  at  the  upper  and  back  part  of  the  Thigh, 
and  upon  thofe  more  immediately  about  the  Joint, — communica- 
ting with  the  Branches  of  the  Circumflexa  Interna. 

The  largeft  Branches  defcend  between  theReflus  Femoris  and 
Vaftus  Externus  ; one,  longer  than  the  reft,  reaching  almoft  as 
far  as  the  outer  part  of  the  Knee. 

The  Profunda  Femoris,  having  detached  the  Circumflex  Ar- 
teries, finks  deep  behind  the  Trunk  of  the  A.  Femoralis,  and  is 
fituated  upon  the  Addufdor  Mufcles  of  the  Thigh. 

In  its  defcent  it  is  divided  into  principal  Branches,  termed 
Rami  Rerfora?ites,  which,  after  fending  off  fmall  Branches  to  the 
Triceps  Mufcle,  perforate  it  to  be  difperled  upon  the  Flexors  on 
the  back  part  of  the  Thigh. 

The  Perforantes  come  off  in  the  following  fucceflion,  viz. 

The  Perforans  Prima , which  arifes  near  the  Small  Trochan- 
ter, perforates  the  Triceps  a little  farther  down,  and  furnilhes 
Branches  to  the  Mufcles  in  the  upper  and  back  part  of  the 
Thigh. 

It  forms  numerous  Communications  with  the  Circumflex  Ar- 
teries, about  the  root  of  the  Great  Trochanter,  and  analtomofes 
in  particular  with  the  under  end  of  the  Sciatica. 

The  Perforans  Secunda  or  Magna,  winch  comes  off  fome-way 
below  the  former,  and  is  the  largeft  of  the  perforating  Arteries. 

It  gives  Branches  to  the  Mufcles  in  general  about  the  middle  of 
the  back-part  of  the  Thigh,  particularly  to  the  Flexors  of  the 
Leg}  and  communicates  above  with  Arteries  of  the  Perforans 
Prima,  and  with  the  Circumflex  Artei ies. 

Befides  thefe,  there  is  one,  and  fometimes  two  other  perfora- 
ting Branches,  which  are  greatly  inferior  in  ftze  to  the  two  for- 
mer, and  are  loft  upon  the  Flexors  at  the  under  and  back  part  of 
the  Thigh  ; one  Twig  fent  off  from  thefe  fometimes  forming  a 
Nutritia  or  Medullaris  of  the  Os  Femoris. 

The  Femoral  Artery,  after  giving  off  the  Profunda  Femoris, 
paffes  down  between  the  Vaftus  Internus  and  infertion  of  the 
Triceps,  giving  only  fmall  Branches  to  the  adjacent  Mufcles  and 
Integuments. 

About  the  middle  of  the  infide  of  the  Thigh,  it  is  fituated  be- 
hind the  Sartorius  Mufcle  ; and  nearly  two-thirds  down  upon 
the  Os  Femoris,  it  perforates  the  Triceps,  paffing  between  that 
Mufcle  and  the  Bone,  in  its  way  to  the  Leg. 

Having  parted  through  the  Triceps,  it  is  found  in  the  back- 
part  of  the  Thigh,  where  it  fends  Branches,  fometimes  termed 


217 


Perforates,  to  the  Flexors  and  Integuments,  one  Branch,  the 
principal  Medullaris,  to  the  fubflance  of  the  Bone,  and  others  to 
each  of  the  Vafti  Mufcles,  the  Mufcular  Branches  communica- 
ting above  with  Branches  defcending  from  the  fuperior  parts  of 
the  Thigh.  In  this  part  of  the  Thigh  it  lies  clofe  upon  the  Bone, 
and  adheres  firmly  to  it,  till  it  reaches  the  Ham,  where  it  is 
termed  A.  Poplitea. 

Arteria  Poplitea. 

The  Arteria  Poplitea  is  lodged  deep  in  the  hollow  be- 
tween the  Ham-ftrings,  and  between  the  Condyles  of  the  Os  Fe- 
moris,  covered  by  its  aftbciate  Vein  and  Nerve,  and  generally  by  a 
great  deal  of  Fat.  . 

It  gives  off  feveral  Branches,  termed  Articulares  Superiores  and 
Jnferiores,  to  the  joint  of  the  Knee. 

Four  of  thefe,  fituated,  two  above  and  two  below  the  Joint, 
are  more  regular  and  canftant  than  the  reft,  viz. 

The  Articularis  Superior  Interna,  which  turns  round  the  Os 
Femoris,  above  the  Inner  Condyle,  paftes  under  the  Semimem- 
branofus  and  Semitendinofus  ; and,  after  perforating  the  Ten- 
don of  the  Triceps  Mufcle,  is  difperfed  upon  the  upper  and  inner 
part  of  the  Knee,  anaftomofing  above  with  Branches  fent  down 
from  the  Femoral  Artery. 

The  Articularis  Superior  Externa,  which  arifes  nearly  oppofite 
to  the  former,  paftes  outwards  between  the  Tendon  of  the  Bi- 
ceps and  Body  of  the  Os  Femoris,  immediately  above  its  outer 
Condyle,  and  is  loft  upon  the  upper  and  outer  part  of  the  Knee  ; 
its  Branches  anaftomofing  with  thofe  of  its  fellow,  and  particu- 
larly with  .the  long  defcending  Branch  of  the  Circumflexa  Ex- 
terna. 

The  Articularis  Inferior  Interna,  which  arifes  oppofite  the 
bending  of  the  Joint,  paftes  downwards,  and  then  turns  round 
the  Tibia,  immediately  below  its  Inner  Condyle. 

It  fiends  Branches  firft  to  the  back-part,  then  to  the  inner  fide 
of  the  Knee  ; fome  of  them  infinuating  by  the  Semilunar  Car- 
tilages into  the  inner  part  of  the  Joint. 

It  communicates  above  with  the  Branches  of  the  Articularis 
Superior  Interna. 

Tht  Articularis  Inferior  Externa,  which  comes  off  near  the 
former,  and  paftes  firft  downwards,  then  outwards,  between  the 
External  Lateral  and  the  Capfuiar  Ligament,  to  be  difperfed  up- 
on the  under  and  outer  part  of  the  Knee  and  inner  part  of  the 
Joint  ; communicating  with  its  fellowof  the  oppofite  fide,  and  a- 
bove,  with  the  Branches  of  the  Articularis  Superior  Externa. 

The  other  lefs  conftant  Articular  Branches  are  difperfed  upon 
the  Mufcles  a little  above  the  Joint. 

VOL.  II.  T 


2 1 S 


The  Arteria  Poplitea,  having  furnifhed  Branches  to  the  Joint 
of  the  Knee,  gives  others  to  the  Mufcles  at  the  upper  and  back 
part  of  the  Leg,  two  of  which,  termed  Surales,  more  confidera- 
ble  than  the  reft,  pafsjnto  the  heads  of  the  Gaftrocnemius  Ex* 
tern  us. 

The  Trunk  of  the  Artery  pafles  afterwards  between  the  heads 
of  the  external  Gaftrocnemius,  and  commonly  from  two  to  three 
inches  below  the  bending  of  the  Knee, •'and  at  the  under  and 
outer  edge  of  the  Popliteus  divides  into  two  large  Arteries,  the 
' Tibialis  Antica , and  Tibialis  Pojiica. 

Tibialis  Antica. — The  Tibialis  Antica  pafles  direftly 
through  the  upper  end  of  the  Interofleous  Ligimentto  the  fore- 
part of  the  Leg. 

In  its  defcent  in  the  Leg,  it  adheres  clofely  to  the  anterior 
futface  of  the  Interofleous  Ligament  ; and  has  the  Tibialis  An- 
ticus  on  the  inner  fide,  and  the  Long  Extenfors  of  the  Toes  on 
the  outer. 

A little  above  the  Ankle,  it  pafles  upon  the  outer  and  fore-part 
of  the  'Tibia,  and  getting  under  the  Annular  Ligament  and  Ex- 
tenfor  Pollicis,  it  goes  along  the  convex  furface  of  the  Foot. 

It  lupplies,  in  general,  the  Mufcles  and  Integuments,  which 
belong  to  the  outer  and  fore-part  of  the  Foot,  and  ultimately  paf- 
fes  into  the  Deep  Mufcles  of  the  Sole. 

Its  Branches  come  off  in  the  following  order,  viz.— 

A Small  Branch  lent  off  before  the  Tiunk  perforates  the  In- 
terofleous L'gament,  to  be  difperfed  upon  the  parts  near  the  Joint ; 
the  fuperior  Twigs  running  in  a retro  rade  direffion. 

The  Recurrens  Anterior,  which  arifes  from  the  Artery  after  it 
has  perforated  the  Ligament,  and  is  difti  ibuied  upon  the  Muf- 
cles at  the  upper  part  of  the  Leg,  and  upon  the  Ligaments  at  the 
under  part  of  the  Knee,  anaftomoftng  there  with  the  Inferior  Ar- 
ticular Ai  teries. 

Numerous  Branches  fent  off  in  a lateral  direfftion  to  the  Mufcles 
and  Integuments  on  the  outer  and  fore-part  of  the  Leg. 

The  Malleoli  Interna,  which  comes  off  near  the  lower  end  of 
the  Tibia,  and  is  difperfed  on  the  parts  about  the  inner  Ankle. 

The  Malleoli  Externa,  which  arifes  a little  lower  than  the 
former,  and  is  d ftributed  to  the  parts  near  the  outer  Ankle. 

The  ArteiiaTarfea,  which  takes  its  origin  a little  anteriorly 
to  the  bending  of  the  Ankle-joint,  and  is  more  conftderable  in 
fize  than  the  Malleolar  Branches. 

It  pafles  obliquely  outwards  and  forwards  under  the  Extenfor 
Brevis  Digitorum,  and  fends  Branches  to  the  Joint  of  the  Ankle, 
where  it  communicates  with  the  Malleolar  Arteries. 

It  fupplies  the  greater  part  of  the  Mufcles,  Integuments,  & c. 
on  the  upper  and.outer  part  of  the  Foot,  and  fends  Branches 
termed  InteroJJ'ei,  to -the  Mufcles  between  the  Metatarfal  Bones  of 


219 


the  fniall  Toes,— which,  however,  are  frequently  derived  from  the 
Metatarfal  Artery. 

The  Arteria:  Metatarfea , which  goes  off  about  the  middle  of 
the  Dorfum  Pedis,  aad  pafles  obliquely  towards  the  root  of  the 
Little  Toe,  aflift'ng  the  former  Artery  in  furnifhing  Branches  to 
the  upper  part  of  the  Foot  and  Toes,  and  fometimes,  in  part  or 
entirely,  iupplying  the  place  ot  that  Artery. 

The  remaining  part  of  the  Anterior  Tibial  Artery  afterwards 
advances  between  the  Extenfor  of  the  gieat,  and  long  Extenfor 
of  the  fmall  Toes,  fending  Twigs  to  the  adjacent  parts,  and  di- 
viding, between  the  Metatarfal  Bones  of  the  Great  Toe  and  that 
next  it,  into  a Large  Pojlerior  and  a Small  Anterior  Branch. 

The  Pojlerior  Branch,  which  tnay  be  coniidered  as  the  con- 
tinuation of  the  Trunk,  finks  between  the  Metatarfal  Bones 
of  the  two  fil'd  Toes,  and  anaftomofes  with  a deep  Artery  in  the 
Sole. 

The  Anterior  Branch  runs  forwards,  under  the  name  of  Dor- 
falis  Pollicis,  to  be  difperfed  upon  the  Gi  eat  and  Second  Toes. 

Tibialis  Postica — The  Tibialis  Poflica  divides  about  a 
finger’s  breadth  under  the  origin  of  the  Tibialis  Antica,  into  the 
Fibularis,  and  Tibialis  Pottica  ftriSlly  fo  called. 

The  Fibularis,  termed  alfo  Peronea,  which  is  fmaller  than 
either  of  the  Tibial  Arteries,  runs  down  at  the  inner  fide  of  the 
Fibula,  for  a confiderable  way  along  the  Leg,  and  is  fituated, 
firft  under  the  Soleus,  and  then  under  the  Flexor  Longus  Pol- 
licis. 

Its  Branches  are  diftributed  to  the  Mufcles  at  the  outer  part  of 
the  Leg  in  the  neiohbourhood  of  the  Fibula, — a fmall  Medullary 
Branch  alfo  penetrating  the  fubdancc  of  that  Bone. 

A little  above  the  inferior  Articulation  of  the  Tibia  and  Fi- 
bula, it  fends  a Branch  forwards,  termed  Peronea  Anterior , 
which  perf  rates  the  Interofleous  Ligament,  and  is  difperfed  up- 
on the  fore-part  of  the  Ankle,  where  it  anadomofes  with  the  Ex- 
ternal Branch  of  the  Tibialis  Antica. 

The  continuation  of  the  Trunk,  fometimes  termed  Peronea 
Pojlerior,  defcends  behind  the  Malleolus  Externus,  to  the  outer 
and  back-part  of  the  Foot,  anaftomofing  with  the  External  Mal- 
leolar and  Tarfal  Branches  of  the  Tibialis  Antica. 

The  Tibialis  Postica,  properly  fo  caded,  pafles  down  at 
the  back-part  of  the  Tibia,  and  runs  over  the  Tibialis  Podicus 
and  Flexor  Digitorum,  and  under  the  Gadrocnemius  Internus, 
in  its  defeent  through  the  Leg. 

Behind  the  inner  Ankle,  it  becomes  more  fuperficial,  and  has 
the  Tibialis  Podicus  and  Flexor  Digitorum  Longus  on  the  inner, 
and  the  Flexor  Longus  Pollicis  on  the  outer  fide  of  it. 

From  the  Ankle,  it  runs  in  the  Hollow  of  the  Os  Calcis,  and 
behind  the  Abduftor  Pollicis,  to  the  Sole  of  the  Foot. 


220 


Its  Branches  fuppJy  the  Mufcles  at  the  back  and  inner  part 
of  the  Leg,  and  the  different  parts  of  the  Sole  ; forming  many 
Inofculations  with  the  Branches  of  the  anterior  Tibial  and  the 
Fibular  Artery. 

In  its  courfe  along  the  Leg,  it  gives  off — 

Numerous  Branches,  fimilar  to  thofeof  the  Tibialis  Antica,  to 
the  furtounding  Mufcles  : 

The  Arteria  Nutritia  Tibia,  which  begins  a little  below  the 
upper  end  of  the  Trunk,  defcends  for  fome  way  in  the  Leg,  and 
gives  Branches  to  the  deep  Mufcles  and  Membranes  near  it,  and 
one  Branch  termed  A.  Medullaris , which  enters  the  Hole  near  the 
middle  of  the  Bone. 

Several  Branches  to  the  parts  behind,  and  at  the  inner  fide  of 
the  Ankle  and  Heel,  which  communicate  with  others  of  the  An- 
terior Tib;al  Artery. 

The  Trunk  of  the  Artery  divides  in  the  Hollow  of  the  Os  Cal- 
cis,  at  the  place  where  it  is  about  to  go  behind  the  Abduftor 
Pollicis,  into  two  principal  Plantar  Branches,— the  Interna  and 
Externa. 

The  Plantar  Arteries  run  forwards  under  the  Aponeurofis 
Plantaris,  having  the  Flexors  of  the  Toes  between  them. 

The  Plantaris  Interna  pafTes  near  tftfc  inner  fide  of  the  Sole, 
between  the  Aponeurofis  Plantaris  and  Abduftor  Pollicis. 

It  gives  Branches  which  run  in  a retrograde  dire&ion  to  the 
back-part  of  the  Ankle  and  adjacent  parts  of  the  Heel  : 

Several  Branches  from  each  fide,  which  go  forwards  to  the 
Mufcles  and  Integuments,  and  other  parts  at  the  concave  edge  of 
the  Sole. 

At  the  root  of  the  Great  Toe,  it  fends  a principal  Branch  to 
its  inner  fide ; it  then  pafTes  under  the  Flexor  Longus  Pollicis, 
and  after  anaftomofing  with  the  Arcus  Plantaris,  gives  off  a 
large  Branch  which  fplits  into  two, — one  to  the  outer  fide  of 
the  Great  Toe,  and  the  other  to  the  adjacent  fide  of  the  Toe 
next  it. 

The  Plantaris  Externa, — which  may  be  confidered  as 
the  continuation  of  the  Trunk,  being  in  general  much  larger  than 
the  Interna.— pafTes  obliquely  outwards  between  the  Flexor  Bre- 
vis Digitorum,  and  Flexor  Accefforius,  till  it  reaches  the  Bale 
of  the  Metatarfal  Bone  of  the  Little  Toe. 

It  is  afterwards  arched  forwards  between  the  Flexors  of  the 
Toes  and  Matatarfal  bones,  the  Trunk  being  continued  to  the 
root  of  the  Great  Toe,  under  the  name  of  Arcus  Plantaris. 

The  External  Plantar  Artery  fends  off — 

A Confiderable  Branch,  firft  to  the  under,  then  to  the  outer  part 
of  the  Heel,  which  communicates  externally  with  Branches  of  the 
anterior  Tibial  and  the  Fibular  Arteries  : 

Several  Branches  to  the  Flexors  of  the  Toes,  and  toother  parts 
n he  outer  portion  of  the  Sole,  which  communicate,  on  the  in- 


221 


ner  fide,  with  the  Branches  of  the  Plantaris  Interna,  and  at  the 
outer  with  thofe  of  the  anterior  Tibial  Artery. 

The  Arcus  Plantaris  gives  out — 

Several  Branches  to  the  deep  Mufcles  of  the  Sole,  particu- 
larly, 

Rami  Interojj'ei  to  the  Mufcles  between  the  Metatarfal  Bones  : 

A Branch  to  the  outer  fide  of  the  Little  Toe  : 

Three  Large  Digital  Arteries,  which  are  forked  at  the  roots  of 
the  Toes,  and  run  along  the  edges  of  thefe,  in  the  manaer  the  Di- 
gital Arteries  do  along  the  Fingers. 

Between  the  Metatarfal  Bones  of  the  Great  Toe  and  the  one 
next  it,  the  Plantar  Arch  analfomofes  with  the  pofterioror  per- 
forating Branch  of  the  anterior  Tibial  Artery,  forming  a free 
communication  between  the  Arteries  of  the  upper  and  under  fide 
of  the  Food.  Frequently  it  fends  off  here  a Digital  Artery, 
which  forks  and  runs  along  the  outer  frde  of  the  Great  Toe,  and 
inner  fide  of  the  Toe  next  it,  fo  as  to  fupply  the  place  of  one  of 
the  Branches  of  the  Internal  Plantar  Artery. 

At  the  roots  of  the  Toes,  the  Interoffeous  Arteries  of  the  up- 
per part  of  the  Foot,  alfo  form  diftinft  ar.aftomofes  with  the  an- 
terior extremities  of  the  Trunks  of  the  Digital  Arteries. 


VEINS. 


The  Veins  of  the  Inferior  Extremities,  like  thofe  of 
the  Superior,  confift  of  a Subcutaneous  and  Deep  fet,  and,  like 
them  alio,  are  furniflied  with  numerous  Valves. 

Subcutaneous  Veins. — The  Subcutaneous  Veins  are  fitu- 
ated  between  the  Common  Integuments  and  General  Aponeuro- 
lis,  and,  in  many  parts,  are  entirely  concealed  by  the  Fat.  They 
anaftomofe  frequently  with  each  other  by  large  Branches,  and 
have  ftveral  communications  alfo  with  the  deep  Teated  Veins. 

They  form  two  principal  Trunks,  called  Saphxna  Major  and 
Saphena  Minor  ; — the  term  Saphaeena  applied,  from  the  Vein 
being  luppofed  to  be  always  vijible. 

The  S a r h /e N a Major  begins  upon  the  upper  fide  of  the 
Foot,  runs  over  the  fore-part  of  the  inner  Ankie,  and  afcends  in 
the  Leg  at  the  inner  edge  of  the  Tibia. 

From  the  Leg,  it  paifes  up  by  the  infide  of  the  Knee,  and  af- 
terwards, from  the  inner  to  the  upper  and  fore-part  of  the 
Thigh. 

It  is  at  firft  compofed  of  Veins,  derived  from  the  upper  and  in- 
ner part  of  the  Dorfum  Pedis,  which  have  frequent  aaaftoinol’es 
with  each  other,  and  are  of  coniiderable  fize, 

Vol.  II.  T 2 


i 


In  its  afcent  it  is  joined  by  Brandies  from  the  fuperficial 
parts  of  the  Leg,  and  is  frequently  fplit  into  a Plexus,  fome  wav 
below  the  Knee. 

It  receives  Branches  from  the  fuperficial  parts  of  the  Thigh, 
and  fma'U  Twigs  from  the  Inguinal  Glands. 

It  terminates  in  the  top  of  the  Femoral  Vein,  nearly  oppofite  to, 
ora  little  higher  than,  the  origin  of  the  Arteria  Profunda. 

The  Saphena  Minor  arifes  upon  the  outer  fide  of  the  Foot, 
and  afterwards  paffes  behind  the  Malleolus  Externus. 

From  this,  it  afcends  in  the  back-part  of  the  Leg,  upon  the 
furface  ot  ihe  Gaftrocnemius  Externus,  and  goes  into  the  ^lam. 

It  is  formed  by  the  Veins  of  the  upper  and  outer  part  of  the 
Foot,  and  is  joined  to  the  Saphasna  Major,  over  the  Metartarfal 
Bones,  by  one  or  more  Arches,  which  receive  a Plexus  of  Bran- 
ches into  their  lower  or  convex  part. 

It  is  joined  by  the  fuperficial  Veins  of  the  outer  and  back-part 
of  the  Leg,  which  have  frequent  anaftomofes  with  each  other, 
and  with  the  Branches  of  the  Saphasna  Major. 

It  terminates  in  the  Vena  Poplitea,  and  communicates  con- 
ftantly  by  a fmall  Branch  with  the  Saphaena  Major,  a little 
above  the  Knee. 

Deep  Veins.  The  Deep  Veins  of  the  Leg,  like  thofe  of  the 
Fore-arm,  run  clofe  at  each  fide  of  their  Arteries,  and  are  dou- 
ble their  number,  but  differ  a little  from  the  Radial  and  Ulnar 
Veins,  in  being  proportionally  larger. 

The  Tibial  and  Fibular  Veins  anaftomofe  in  fome  places 
with  each  other,  and  alfo  communicate  with  the  Subcutaneous 
Veins. 

At  the  upper  part  of  the  Leg,  they  are  united  together,  to  form 
the  Vena  Poplitea,  and  the  union  is  nearly  at  the  fame  place 
where  the  correfponding  arteries  come  off 

The  Vena  Poplitea  adheres  clofely  to  the  upper  furface  of 
the  Artery,  which  it  in  a great  mealure  conceals,  and  is  com- 
monly fingle,  excepting  a fmall  Vein  which  fometimes  accom- 
panies and  communicates  with  it. 

The  Popliteal  Vein  receives  the  Venae  Surales  and  Articulares, 
and  the  Saphaena  Minor;  after  which  it  forms  the  Femoral  Vein. 

The  Vena  Femoralis  receives  the  Veins  which  correfpond 
with  the  perforating  Branches  of  the  Femoral  Artery,  and  paffes 
in  through  the  Triceps,  where  the  Artery  cornesout. 

In  the  middle  of  the  Thigh,  it  lies  deeper  than  the  Artery, 
afterwards  turning  gradually  to  its  inner  fide  ; and  at  the  upper 
part  of  the  Thigh,  it  is  joined  by  the  Vena  Profunda. 

The  Vena  Prounda  receives  the  Veins  correfponding  with 
the  Branches  of  the  Artery  of  that  name,  and  is  fometimes  of  a 
large  fize,  being  then  in  a great  meafure  the  continuation  of  the 
Vena  Poplitea,  a fmall  Vein  only  in  fuch  cafes  accompanying 
the  Trunk  ot  the  Femoral  Artery. 


223 


Befides  the  Vena  Profunda,  the  Femoral  Vein  takes  in  fmall 
Veins  from  the  External  parts  of  Generation,  from  the  Ingui- 
nal Glands,  and  from  the  other  fuperficial  parts  of  the  Groin  : 
-—and,  in  particular,  it  receives  a Branch  of  confiderable  fize, 
which  defcends  from  the  Integuments  of  the  fore-fide  of  the  Ab- 
domen. 

The  Trunk  of  the  Femoralis,  having  received  the  different 
Veins  of  the  Inferior  Extremity,  pafles  into  the  Abdomen,  be- 
hind Poupart’s  Ligament,  being  ttill  fituated  at  the  inner  fide 
of  the  Artery, — after  which  it  forms  the  Iliaca  Externa. 

The  Iliaca  Externa  receives  into  its  beginning  the  Epi- 
gaftric,  and  Circumflex  Vein  of  the  Os  Ilium,  and  fometimes  the 
V.  Obturatrix. 

It  is  fituated  at  the  infide  of  the  External  Iliac  Artery,  and 
afterwards  erodes  behind  it  on  the  right,  and  behind  the  Inter- 
nal Iliac  Artery  on  the  left  fide  of  the  pelvis,  to  join  the  Trunk 
of  the  Hypogaftric  Vein. 

The  Vena  Hypogastric  a,  or  Iliaca  Interna,  is  fitu- 
ated at  the  outer  fide  of  the  Artery  and  receives  the  different 
Veins  which  correfpond  with  the  Branches  of  the  Hypogaftric 
Artery,  and  which  are  furnifhed  with  Valves  where  they  are 
fituated  among  the  Flefhy  parts  of  the  Pelvis. 

The  External  and  Internal  Iliacs  unite  and  form  the  Common 
Iliacs,  a little  below  the  divifion  of  the  correfponding  Arte- 
ries. 

The  Iliac.®  Communes  afeend  by  the  right  fide  of  their 
refpadlive  Arteries,  and  a little  below  the  the  Bifurcation  of  the 
Aorta,— or  upon  the  fore  part  of  the  Fifth  Lumbar  Vertebra, — 
unite  to  form  the  Inferior  Cava,  fituated,  as  formerly  mentioned, 
at  the  right  fide  of  the  Aorta. 

The  Vena  Cava  Inferior, — which  is  much  larger  than 
the  Cava  Superior,  and  greatly  exceeds  in  fize  the  defeending 
Aorta,— receives,  at  its  beginning,  the  Vena  Sacra,  and  higher, 
the  Venae  Lumbares,  which,  in  the  left  fide,  pafs  behind  the 
Trunk  of  the  Aorta. 

It  likewife  receives  the  Venae  Renales,  and  the  Spermatica  of 
the  right  fide. 

At  length  it  takes  in  the  Venae  Hepaticas  and  Diaphragma- 
ticae,  and  perforating  the  Diaphragm  at  the  root  of  the  Liver,  it 
terminates  in  the  Right  Auricle  of  the  Heart. 


224 


PART  VII. 


OF  THE 


NERVES  IN  GENERAL . 


THE  Nerves  are  firm,  white  Cords,  which  are  generally 
confidered  as  being  direftly  continued  from  the  Medullary 
Subftance  of  the  Brain  aftd  Spinal  Marrow  ; — although  inftan- 
ces  have  been  frequently  met  with,  where  the  Brain,  and  even 
the  Spinal  Marrow,  have  been  found  nearly  obhteratcd  in  the 
Foetus,  and  yet  the  Nerves  retained  their  ufual  appearance. 

They’  are  e .mpofed  of  Funiculi  clofely  connected,  and  each  of 
thel'e  again  of  fmailer  Fibrilla:  which  may  be  fubdivided  into  parts 
fo  extremely  minute,  as  almoft  to  elude  the  naked  Eye,  but 
which  may  be  readily  feen  by  the  afiiftance  of  the  M crolcope  : 
-—No  Cavity,  however,  has  been  yet  obferved  in  them. 

The  Medullary  Part  of  the  Fibrillae  appears  to  be  furniftied 
with  Cineritious  Subftance  derived  from  their  Pia  Mater;  in 
proof  of  which,  they  are  obfeived  to  be  in  general  of  a browner 
colour  than  the  Medullary  Subftance  of  the  Brain,  and  larger 
in  their  courfe  than  at  their  fuppofed  origin. — Mon-ro’s  Obf.  on 
Nerv.  Syjl. 

The  Medullary  Subftance  of  the  Fibrillae  is  pulpy  and  tender, 
but  rendered  thicker  and  ftronger  by  the  coverings  they  receive 
from  the  Tun  ca  Arachnoidea,  and  Pia  Mater,  while  within  the 
Bones,  and  more  particularly  by  the  additional  covering  given 
them  by  the  Dura  Mater  upon  their  exit. 

The  Dura  Mater,  in  its  paffage  through  the  Bafe  of  the  Cra- 
nium, and  between  the  different  Vertebrae,  is  connected  by  its 
External  Surface  to  the  Pericranium  and  Periofteum;  while 
the  inner  part  of  it,  together  with  the  Tunica  Arachnoidea  and 
Pia  Mater,  is  continued  along  the  Nerves. 


225 


The  Involucre.,  or  Coverings,  inclofe  each  of  the  Nerves  in 
genera!,  and  likewife  the  fevera!  Fibrillae  of  which  they  are  com- 
pofed,  whereby  their  fize,  as  well  as  Itrength,  is  greatly  in- 
creafed. 

The  Nerves,  foon  after  leaving  the  Bones,  have  the  Dura 
Mater  fo  intimately  connected  with  them,  that  it  has  been  con- 
fidered  by  fome  Authors,  as  degenerating  into  condenfed  Cellular 
Sublfance,  notwithftanding  it  itill  retains  the  general  appearance 
of  the^Dura  Mater. 

Upon  examining  the  Nerves,  efpecially  the  fmall  ones,  in  a 
living  or  recently  dead  animal,  they  are  obferved  to  have  nume- 
rous White  Lines  placed  tranfverfely,  or  in  a Terpentine  direction. 
—Obf.  on  Nerv.  Syfi.  Tab.  XIII. 

When  the  Nerves  are  moderately  ftretched,  this  appearance 
becomes  lefs  evident;  and  when  extended  conliderably,  or  when 
macerated  in  water,  it  vanilhes  entirely. 

Prochaska  (Be  Carne  Mufculari)  fuppofes  thefe  Serpen- 
tine Lines  to  be  owing  to  a decuffation  of  Veflels  and  Fibres  of 
Cellular  Sublfance  ftraitening  the  Nerves. 

Dr.  Monro  confiders  them  as  Folds  or  Joints  allowing  the 
Nerves  to  accommodate  themfelves  to  the  various  ftates  of  Flex- 
ion and  Extenfion. 

The  Nerves  are  fupplied  with  Arteries  from  the  neighbouring 
Blood- veflels,  to  which  they  fend  correfponding  fains. 

Thefe,  however,  are  fmall,  and  difficult  of  injection,  except- 
ing in  the  large  Nerves,  where  the  Velfels  are  more  confiderable, 
and  where,  after  a minute  injection,  the  Nerve  receives  the  colour 
cf  the  matter  injeCted. 

Upon  dividing  the  Nerves,  they  are  not  found  to  poffefs  much 
contraFlilily  ; while  the  Arteries,  upon  being  cut  are  obferved  to 
retraCt  very  confiderably . 

They  are  generally  lodged  in  the  common  Cellular  Subftance 
and  Fat,  and  in  the  Interftices  of  the  Vifcera  and  Mufcles,  where 
they  are  prevented  from  being  compreffed  ; though  in  feveral  parts 
they  are  expofed  to  the  hardnefs  of  Bones,  or  to  the  aCtion  of 
Mufcles,  over  or  through  which  they  pafs. 

In  their  courfe  through  the  different  parts  of  the  Body,  they 
generally  run  as  ftraight  as  is  confident  with  the  nature  of  the 
particular  part  over  which  they  pafs,  an  J their  own  fafety. 

In  their  progrefs,  they  divide  into  Branches,  which  become 
gradually  fmaller,  and  which,  though  taken  collectively,  are  in- 
ferior in  fize  to  the  Trunks  from  which  they  iffue. 

The  Branches  generally  run  off  at  acute  angles  ; but  in  feveral 
places  they  have  a retrograde  direction. 

They  have  commonly  the  fame  kind  diftribution  in  the  oppofite 
tides  of  the  fame  SubjeCt,  and  vary  little  in  this  refpeCt  in  diffe- 
rent Subjects. 


226 


In  fome  parts  of  the  Body,  feveral  Nerves  unite  together,  and 
form  a Plexus  or  Net-work  ; in  other  , they  unite  into  a Connnon 
Trunk-,  and  in  many,  by  fuch  an  union,  a hard  knot,  termed 
Ganglion,  is  formed. 

When  tlie  Plexufcs,  or  the  Common  Trunks,  are  minutely  ex- 
amined by  flitting  open  their  coverings,  it  is  found,  that  their 
Fihriliae  are  intermixed  in  fuch  a manner,  that  each  of  the 
Nerves  pafling  out  from  the  Plexus,  or  from  the  Common  Trunk, 
is  comp  ,fed  of  Fibrillae  from  feveral,  or  from  ail  the  NerTes 
which  en  ered  it,  in  confequence  of  which,  the  Organs  in  gene- 
ral are  furn  ftud  with  Nerves  fiom  various  fources.  Obf.  on 
Nerv.  Syft. 

The  Ganglia  differ  from  each  other  in  flze  and  figure  : They 
have  thicker  Coats  and  are  more  Vufcular  than  the  Nerves  ; and 
are  larger  than  the  whole  of  the  Nerves,  taken  conjunftly,  which 
entc-r  into  or  go  out  from  them. — f hey  are  fuppoled  to  ferve  as 
fiefh  fources  of  Nervous  Influence. 

They  a e computed  of  Neivous  Fibrillx,  covered  by  fomething 
like  a Cineritious  Matter,  and  are  fo  divided,  multiplied,  and 
intei  mixed,  that  each  of  the  Nei  ves  pafling  out  from  a Ganglion 
is  found  to  be  compof'ed  of  Fibrillae  derived  from  the  greater  part 
of  the  Nerves  which  enter  it. — Obf.  onNerv.  Syft. 

Where  Nerves  pals  out  from  the  fide  of  a Ganglion,  they 
are  compofed  of  Fibrillae  which  come  off  in  contrary  directions ; 
— the  one  let  from  the  beginning,  the  other  from  the  oppo- 
fite  extremity  of  the  Ganglion. 

The  Nerves  which  go  out  from  the  different  Ganglia  have  the 
fame  ftru&ure  with  thole  which  enter  them,  but  are  found,  with 
only  a few  exceptions,  to  be  rather  la.ger. 

In  the  Trunk  of  a Nerve,  the  Cords  appear  to  run  parallel  to 
each  other  ; but  when  macerated  in  water,  fo  as  to  diffolve  the 
Cellular  Subftance,  or  when  otherwife  accurately  examined,  they 
are  feen  evidently  to  intermix  fomewhat  after  the  manner  of  the 
Fibrillae  in  the  Plexus,  or  in  the  Ganglia. — Obf.  on  Ner<v. 
Syft  an. 

The  Termination  of  the  Nerves  is  fuft,  pulpy,  and  pellucid, 
as  is  dill  ndtly  feen  in  the  Retina  of  the  Eye  or  Ear  ; the  exter- 
nal Covering  being  entirely  laid  afide,  while  the  Pia  Mater,  in 
particular,  accompanies  them  throughout. 

The  Nerves  preferve  the  motion  of  the  Mufcular  Fibres. 

They  conflitute  the  immediate  Organs  of  Senfation,  and  con- 
vey Impreflions  made  upon  them  to  the  Mind. 

The  manner  in  which  thefe  Impreflions  are  produced,— whe- 
ther by  a Vibration  communicated  to  the  Nerves;  or  by  a Liquid 
called  Nervous  Fluid,  contained  and  moving  in  them  or  by  an 
eleftric  Matter  common  to  them  and  many  other  fubftances  ; or 
in  what  manner  that  power  a els,  termed  Animal  Electricity, 


227 


which  has  been  la'ely  difcovered  to  take  place  in  the  Animal 
Kingdom,  upon  the  application  of  certain  Metals  ; is  not  yet 
underftood. 


DISTRIBUTION  OF  THE  NERVES. 

THE  Nerves  are  diftinguifhed  into  two  Clafles  ; one  arifing 
from  the  Biain,  termed  Cerebral ; the  other  from  the  Spinal  Mar- 
row, teimed  Spinal  Ner-ves. 

The  Cerebral  Nerves-are  generally  reckoned  Nine  or  Ten  Pairs 
in  number,  befides  a particular  Pair,  which  has  the  name  of 
Sympathetic. 

They  pafs  through  the  Holes  iu  the  Bafe  of  the  Cranium,  and 
receive  their  refpeftive  Names  according  to  their  order  ; or  from 
their  Functions  5 or  from  the  parts  on  which  they  are  difperfed,  &c. 

The  Spinal  Nerves  con  fill  of  Tnxienty-Nine  or  7 hirty  Pairs, 
which  pals  out  between  the  d fferent  Vertebrae,  befides  a Pair 
called  Accejfory,  which  enter  the  Cranium  from  the  top  of  the 
Spinal  Marrow,  and  afterwards  pafs  out  with  one  of  the  Cerebral 
Nerves. 

Nerves  which  pass  through  the  Base  of  the 
Cranium. 

The  First  Pair,  or  Olfactory  Nerves, — arife,  on 
each  fide  of  the  Brain,  by  three  feparate  Striae,  from  the  Cor- 
pora Striata,  at  the  under  and  back-part  of  the  Anterior  Lobes, 
near  where  the  Carotid  Arteries  enter  the  Fijfures  of  Sylvius. 

They  are  more  tender  than  the  other  Nerves,  and  alfo  differ 
from  them  in  not  being  compofed  of  Fafcicub. 

They  run  each  in  a Furrow,  upon  the  under  Surface  of  the 
Anterior  Lobes  of  the  Brain,  converging  a little  and  becoming 
fomewhat  larger,  till  the)  reach  the  Cribriform  Plate  of  the 
OEthmoid  Bone. 

Upon  this  Plate,  each  forms  an  Oblong  Bulb,  which,  in  colour 
and  confidence,  rei’embles  the  Cortical  part  of  the  Brain,  but  is 
mixed  with  (Leaks  of  Medullary  Matter. 

From  this  Bulb,  numerous  Nervous  Filaments  are  fent  off, 
which  pafs  through  the  Holes  tf  ihe  Cribriform  Plate,  and  now 
become  firm  and  ftrong  like  the  other  Nerves,  by  receiving  a co- 
vering from  the  Dura  Mater. 

After  entering  the  Nofe,  they  divide  into  two  Portions  or 
Planes, — one  paffing  on  the  Septum,  the  other  upon  the  Olfa  Tur- 
binara,  and  other  parts  oppofite  to  the  Septum,  and  both  running 
at  firft  in  Grooves  of  the  Bones. 


22S 


They  form  a beautiful  Plexus,  which  is  fpread  out  upon  that 
fide  of  the  Membrane  of  the  Nofe  which  is  contiguous  to  the 
Bones,  and  may  be  traced  a confiderable  way  upon  it  in  diftinfl 
Threads,  which  becoming  gradually  fmaller,  fink,  into  the  Mem- 
brane, and  are  fuppofed  to  terminate  on  the  1'uiface  next  the  Ca- 
vity of  the  Nofe,  theie  conftituting  the  Organ  of  Smell. 

The  Second  Pair,  or  Optic  Nerves, — which  are  of  great 
fize,  arife  from  the  Thalami  Optici,  and  are  connefled  in  their 
paffkge  to  Tubercles  at  the  root  of  the  Infundibulum,  which 
furnifh  them  with  an  addition  of  Medullary  Subftance. 

They  are  of  a purer  white  than  other  Nerves,  having  lefs  Ci- 
neritious  Matter  entering  their  compofition,  and  differ  alfo  in 
the  Pia  Mater  furn  fhing  them  with  a general  Covering,  before 
it  invelts  the  feverai  Falciculi  of  which  they  are  formed. 

At  the  fore  part  of  the  Sella  Turcica,  they  unite,  and  have 
their  Medullary  Parts  intimately  intermixed. 

From  this  union,  they  go  obliquely  outwards  and  forwards 
through  the  Foramina  Optica  into  the  Orbits;  and  advancing  in 
the  Orbits  in  a waving  dirtflion,— i o prevent  them  from  being 
over-lfretched  in  the  motions  of  the  Eye, — they  perforate  the 
Balls,  to  be  expanded  into  the  Retinae,  which  have  been  already 
deferibed. 

The  Third  Pair,  or  Motor  es  Ocui.orum, — fmaller  than 
the  Optic  Nerves, — arife  at  the  under,  inner,  and  back-part  of 
the  Crura  Cerebri,  or  between  the  Corpora  Albicantia  and  Tu- 
ber Annulare,  by  numerous  Threads  which  are  foon  collefted 
into  their  refpe&ive  Trunks. 

They  pafs  outwards,  perforate  the  Dura  Mater  at  the  (ides  of 
the  Porter ior  Clinotd  Procefs,  and  running  along  the  upper  part 
of  the  Cavernous  Sinus,  at  the  outfide  of  the  Carotid  Arteries, 
they  get  through  the  Foramina  Lacera  into  the  Orbits. 

Upon  entering  the  Orbits,  they  divide  into  feverai  Branches, 
which  fupply  the  greater  number  of  the  Mufcles  of  the  Eye,  in 
confequence  of  which  the  Nerves  have  obtained  their  particular 
name. 

A Btanch  runs  to  each  of  the  Mufcles  within  the  Orbit,  ex- 
cepting the  Trochlearis  and  Abduftor  ; and  the  Nerve  likewife 
aflilts  in  forming  a final)  Ganglion,  termed  Optbalmic,  from 
which  Twigs  are  fent  off  to  fupply  the  Ball  of  the  Eye. 

The  Fourth  Pair,  or  Pathetic. — have  their  origin  the 
higheft  of  the  Cerebral  Nerves,  and  are  the  moft  (lender  of  the 
Body,  being  generally  formed  of  one  Fafciculus  only  on  each 
fide. 

They  arife  by  a Angle,  and  fometimes  by  a double  root,  behind 
the  Teftes,  from  the  Medullary  Expanfion  which  lies  over  the 
paflage  to  the  Fourth  Ventricle,  and  which  unites  the  Proceflus 
ad  Teftes  to  each  other. 


229 


They  afterwards  turn  round  the  Crura  Cerebri,  and  perforate 
the  Dura  Mater  at  the  edges  of  the  Tentorium,  fome  way  behind 
the  entrance  of  the  Third  Pair. 

They  run  afterwards  along  the  Cavernous  Sintifcs,  at  the  outer 
fide  of  the  Third  Pair,  then  crol's  over  that  Pa  c,  and  pa.Ting 
out  of  the  Cranium  through  the  Foramina  Laceri,  the.  go  ob- 
liquely over  the  Mufcles  at  he  upper  part  of  the  Orbits,  to  be 
entirely  d.fperfed  upon  the  Pathetic  or  Trochlearis  Mui’cles. 

The  Fifth  Pair,  or  Par  I rigeminum, — which  are  the 
largeft  Nerves  of  the  Brain,  arife,  each  by  an  an  erior  fmall,  and 
a pofterior  large  Portion,  from  the  fide  of  the  Tuber  Annulare, 
where  the  Crura  Cerebelli  join  it. 

They  enter  the  Dura  Mater  a little  below  the  Tentorium,  over 
the  points  of  the  Partes  Petrofae  of  the  Temporal  B ties,  and 
form  a Plexus  on  each  fide,  in  which  upwaids  of  fifty  Faicicu- 
li  have  frequently  been  enumerated. 

The  Plexus  finks  clofe  by  the  outfide  of  the  Cavernous  Sinus, 
concealed  by  a doubling  of  the  Dura  Mater,  and  foirns  a Gang- 
lion fometimes  called  Gajferion , after  Gasser,  who,  if  not  the 
Difcoverer,  was  the  firft  who  illuftrated  it. 

The  Ganglion  is  of  a fem’lunar  firm,  and  placed  tranfverfely 
with  refpefl  to  the  Trunk,  of  the  Nerve. 

From  the  oppofite  and  curved  edge  of  the  Ganglion,  three  large 
Branches  come  out ; the  firft  and  An  erior,  termed  Ophthalmic , 
—the  fecond  and  Middle,  the  Superior  Maxillary , and  the  third 
nd  Polferior,  the  Inferior  Maxillary . 

The  First  Branch  of  the  Fifth  Pair, — at  the  fide  of  the 
Sella  Turcica,  is  fituated  lower  than  the  Third  Pair,  and  after- 
wards erodes  over  it,  being  previoufly  connefted  by  Nervous 
Matter  to  the  Trunk  of  the  Fourth  Pair. 

It  goes  through  the  Foramen  Lacerum  into  the  Orbit,  and  is 
there  divided  into  the  following  Branches,  viz. 

The  lupra-Orbitar,  which  is  the  largeft  of  the  whole,  being 
a continuation  of  the  Ophthalmic. 

It  pafles  immediately  under  the  Membrane  which  lines  the  up- 
per part  of  the  Orbit,  and  fplits  into  two  branches  of  unequal 
fize. 

The  fmaller  Branch  termed  Supratrochlearis,  runs  under  the 
Superciliary  Ridge  to  the  Upper  Eye-lid  and  Fore-head. 

The  larger  paffes  through  the  Foramen  Supra-Obitarium,— or 
over  the  Superciliary  Ridge  when  the  Foramen  is  awanting,— 
fends  Branches  to  the  Upper  Eye-lid,  and  divides  into  feveral 
others,  which  run  back  partly  above,  but  chiefly  under  the  Fron- 
tal Mufcle,  to  fupply  the  fore  at  d upper  part  of  the  Head  in  ge- 
neral, while  minute  Fibres  appear  to  penetrate  the  Bones. 

The  Nafal  Branch , which  runs  obliquely  over  the  Optic 
Nerve,  where  it  detaches  a Filament  or  two  to  the  Eve,  them 
under  the  Levator  Mufcles  of  the  Eye-lid  and  Eye:  and  getting 

Vol.  II.  U 


230 


between  the  Abdu&or  Oculi  and  Trochlenris,  pafles  to  the  infide 
<of  ihe  Orbit. 

It  fends  a Branch,  which  after  entering  the  Foramen  Orbitari- 
um  Internum  Anterius,  re-enters  the  cavity  of  the  Cranium,  and 
gets  upon  the  Cribriform  Plate  of  the  OEthmoid  Bone. 

From  thence  it  pafles  down  through  one  of  the  anterior  Holes  of 
this  Plate,  and  fends  Twigs  to  tho  membrane  at  the  anterior  part 
of  the  Nolttil,  while  the  Nerve  defcendi ng  at  the  fore  part  of  the 
Septum  Narium,  is  difperfed  upon  the  point  and  Wing  of  the 
Nofe. 

The  continuation  of  the  Nafal  Branch,  new  called  Infratroch- 
learis,  paffes  forwards  to  the  inner  Corner  of  the  Eye,  and  is 
-diftributed  upon  the  Lacrymal  Sac  and  parts  adjacent. 

The  Lacrymal  Branch,  which  runs  along  the  Abduftor  Oculi 
Mufcle,  fends  Twigs  to  the  Membranes  and  Fat  near  it,  likewife 
one  or  two  through  the  Subftance  of  the  Cheek-bone,  and  one  in 
particular  to  the  Subftance  of  the  Lacrymal  Gland,  while  ano- 
ther paffes  over  the  Gland,  and  vanifhes  in  the  neighbouring 
parts. 

A Branch  to  the  Ophthalmic  Ganglion,  which  is  fometimes  fent 
off  from  the  Nafal,  at  other  times  from  the  Ophthalmic  Trunk. 

The  Ophthalmic  Ganglion, — termed  all'o  Lenticular,  from  its 
fhape,  is  formed  by  this  Branch  from  the  Fifth,  and  by  another 
from  theTh'rd  Pair,  and  is  commonly  the  fmalleft  in  the  Body. 

It  is  of  an  oblong  form  and  compreffed,  is  fituatedat  the  out- 
did e of  the  Optic  Nerve  a little  before  its  entrance  into  the  Orbit, 
and  is  concealed  in  Fat.  Sometimes,  though  rarely,  the  Fila- 
ments which  form  it  take  their  origin  entirely  from  the  Third 
Pair. 

From  the  Ganglion,  about  a dozen  of"  Filaments  arife,  termed 
Ciliary  Nerves,  colle&ed  into  two  Portions,  which  cteep  along 
the  oppofite  tides  of  the  Optic  Nerve,  feparated  a little  from  each 
other  and  running  in  company  with  the  Ciliary  Arteries. 

Befides  the  Ciliary  Nerves  from  the  Ganglion,  one  and  fome- 
times two  Filaments  arife  from  the  Ramus  Nafalis,  and  pafs 
along  with  the  other  Ciliary  Branches, 

The  Ciliary  Nerves,  running  with  fcarcely  any  divifion,  reach 
the  back-part  of  the  Eye  ; and  a little  before  the  Infertion  of  the 
Optic  Nerve,  enter  the  Sclerotic  Coat,  pafs  obliquely  through  it, 
-and  about  the  middle  of  the  Ball,  appear  upon  the  Surface  of  the 
Tunica  Choro'des. 

Upon  this  Coat,  they  run  flat,  and  in  a parallel  dire&ion, 
fending  very  few  evident  Branches,  either  to  it  or  to  each  other, 
till  they  reach  the  Ciliary  Circle,  where  they  divide  into  nume- 
rous minute  Filaments. 

Upon  the  Chotoides,  five  or  fix  are  larger  than  the  reft,  fome 
being  fo  minute  as  almoft  toefcape  the  naked  Eye. 


231 


At  the  Ciliary  Circle,  each  commonly  divides  into  two  Bran- 
ches, which  are  covered  by  the  Cellular  Subftance  of  the  Circle  ;■ 
and  thefe,  at  th.  n>ot  of  the  Irs,  are  fubdividcd  into  ftill  fmaller 
Branches,  which  mu  in  a radiated  and  waving  dire&ion,  the  Ci-- 
liary  Veflels  being  interpofed. 

Near  the  inner  -dge  of  the  Pupil,  they  are  united  into  Arches,’ 
from  wlvch  very  minute  Twigs  run  to  the  interio  r margin  of  the 
Iris. 

The  Second  Branch,  or  Superior  Maxillary  Nerve, 
—is  larger  than  the  Ophthalmic,  and  is  principally  difperfed 
upon  the  Parts  belonging  to  the  Upper  Jaw,  trom  which  ir  has 
its  name. 

It  goes  through  the  Foramen  Rotundum  of  the  Sphenoid  Bone, 
and  at  its  exic  divides  into  numerous  Branches,  viz. 

The  Spheno- P alatine,  or  lateral  Nafal  Ner-ve,  which  fends  a 
reffcft-d  Branch  through  the  Foramen  Pterygoideum  of  the  Sphe- 
noid Bu  ie,  to  join  the  Sympathetic  Nerve  in  the  Canalis  Caroti- 
cus,  and  a Branch  winch  en.eis  the  Foramen  Innominatum  of  the 
Pars  Petroi’a,  to  join  the  Portio  Dun  of  the  Seventh  Pair. 

Tile  Lateral  Slain  Nerve  goes  afterwords  into  the  Spheno- 
palatine Hole,  to  be  dilpened  upon  the  under  and  back-part  of  the 
Septum,"  and  oppoiiie  fide  of  the  Nofe,  ami  upon  the  Membrane 
of  the  Sphenoidal  Smus  and  Euttachian  Tu:  e : One  Branch  in 
Dart  icular,  atter  ...  ;g  along  the  Septum,  -rues  throuca  the  F«-- 
ramcn  Incifivum  ■ . le  Roof  of  the  Mouth. 

The  P alato  Iy atctlla -j , or  Palatine , Branch . which  defcends 
through  the  Canal  .eudiug  r lie  Foramen  Paiat'num  Poller i us  j 
and  running  near  i ae  Aiv;  with  con  ei'poml  ng  Biood  -veflels, 
fends  Branches  to  the  Velum  F a and  Roof  of  the  M m,h,  and 
Minute  F 'aments  wh:  h penetrate  into  the  Palate  plate  of  the 
Superior  Maxillary  Bone. 

Small  Branches,  waich  pals  round  the  Upper -Jaw,  and  vanilla 
in  the  Cheek. 

A Twig,  which  goes  through  the  H de  in  F O-  Mils?,  along 
with  a Branch  of  the  Ocular  Artery,  to  ik  - 

Small  Filaments,  which  run  down  uuo  ■ . h ,r  n-  ;-c  • f . he  Su- 
perior Maxillary  Bone,  and  fupply  the  fu  dime  die  Up.-r- 
Jaw,  tne  large  Dentes  M.olares,  and  Nlcunbiane  lnurp  the  t a - 
trum  Maxillare. 

The  Second  Part  of  the  Fifth  Pair  after  fending  off  theft-  af- 
ferent Branches,  goes  into  the  Canal  under  the  Oibit,  and  fotras 
the  Infra-orbitar  Nerve,  which,  while  in  the  Can-  1,  gives  off 
Filaments  pafling  through  minute  Conduits  in  the  Upper  Jaw.  to 
the  Antrum,  to  the  Subftance  of  the  Bone,  to  the  fimll  Mod  ,-cs, 
Caninus,  Incifores,  and  Fore-Teeth  ; and  fometimes  a Tv 
the  companion  of  a fnial!  Branch  of  the  Internal  Maxillary  Ar- 
tery, to  the  Membrane  lining  the  Orbit. 


S32 


The  Jnfra-Orbitar  Nerve  pafles  afterwards  out  of  the  ForameE 
Infra  Oibitariuin,  and  divides  into  many  large  branches,  to  be 
diftn'uited  upon  the  Check,  Und  er  Eye-lid,  Upper  Lip,  and  fide 
of  the  Nufe. 

Tiie  Third  Branch,  or  Inferior  Maxillary  Nerve, 
goes  i hough  - he  Foramen  Ovale  of  the  Sphenoid  Bone,  and  Top- 
plies  i he  parts  belonging  to  the  Under  Jaw,  and  the  Mufcles  fitu- 
ated  between  it  and  the  Os  Hyoides,  by  the  following  Branches, 
Viz. 

One,  or  fomeimes  two  Deep  Temporal  Branches,  to  the  inner 
part  of  the  Temporal  Mulcle. 

Branches,  to  the  Maffeter,  Pterygoideus,  and  Buccinator 
Mufcles. 

A Branch  wh  ch  pafles  behind  the  Cervix  of  the  Lower  Jaw, 
and  r ives  off  Filaments  to  the  fore-part  of  the  Ear,  and  after- 
wards accompanies  the  Temporal  Artery  upon  the  fide  of  the 
Head,  where  it  terminates. 

A Branch,  to  the  Buccinator  Mufele  and  other  parts  of  the 
Cheek.  * 

A Nerve  of  confiderable  fixe,  termed  Lingual  or  Gujlatorius, 
which  pafles  between  the  Pterygoid  Mufcles,  to  the  inner  of 
which  it  gives  lome  Filaments.  It  then  fends  off,  from  its  un- 
der fide,  a Ganglion  which  tranfmits  Nerves  to  the  Inferior  Max- 
illary Gland. 

The  Lingual  Nerve  alfo  tranfmits  feveral  Branches  to  the  Sub- 
lingual Gland,  and  to  the  Mufcles  of  the  Tongue. 

It  tei  minutes,  at  length,  near  the  Point  of  the  Tongue,  by 
many  Branches  which  belong  chiefly  to  the  Papillae  ; in  confe- 
quence  of  which  this  Bianch  is  confidered  as  the  principal 
Nerve  of  the  Organ  of  Tafte. 

The  .Trunk  of  the  Inferior  Maxillary  Nerve,  having  parted 
wit'n  the  Lin  ual  Nerve,  direfls  irscourfe  between  the  Pterygoid 
Mufcles  to  the  Polierior  Foramen  of  the  Infeiior  Maxillary 

Canal. 

Before  entering  the  Canal,  it  fends  off  a long  and  {lender 
Bianch,  which  is  lodged  at  firft  in  a Furrow  of  the  Bone,  and 
goes  afterwards  to  be  difperfed  chiefly  upon  the  Mylo-hyoideus 
Mufele  and  Sublingual  Gland. 

The  Trunk  of  the  N'-rve  is  afterwards  conduced  along  the 
Canal  of  the  Jaw  under  the  Alveoli,  where  it  diftributes  Fila- 
ments to  the  different  Teeth  of  the  cot  refponding  fide,  and  to 
the  Subflance  of  the  Bone  : and  coming  out  of  the  Canal  by  the 
Anterior  Maxdlary  Foramen,  fomewhat  diminiflied  in  fize,  it 
fcatters  its  remaining  Branches  upon  the  Chin  and  under  Lip. 

The  Sixth  Pair,  or  Abducentes,  arife  from  the  begin- 
ning of  the  Medulla  Oblongata,  at  the  pait  common  to  the  Tu- 
ber Annulare  and  Corpora  Pyramidalia,  and  are  the  fmallelt  of 
the  Cerebral  Nerves,  the  Fourth  Pair  excepted. 


233 


They  perforate  the  Dura  Mater  at  the  inner,  fide  of  the  en- 
trance of  the  Fifth  Pair,  and  run  forwards  within  the  Cells  of 
the  Cavernous  Sinus  5 but  fo  funounded  by  Cellular  S 1 1 bltance, 
as  to  feem  to  be  protefled  from  the  Blood  of  that  Receptacle. 

While  in  the  Sinus  Cavernofi,  they  are  Situated  between  the 
Ophthalmic  Nerves  and  Carotid  Arterie-,  upon  the  furface  of 
the  latter  of  which  they  fend  off  two  or  three  Filaments  on 
each  fide  of  the  Head,  to  ailift  in  forming  the  Great  Sympathetic 
Nerves. 

The  Trunks  of  the  Sixth  Pair  afterwards  go  through  the  fo- 
ramina Lacera,  to  be  dilperfed  entirely  upon  the  Abductor  Mui- 
cles  of  the  Eyes. 

The  Seventh  Pair  is  compofed,  on  each  fide,  of  two  porti- 
ons,— the  Nervus  Auditorius,  Nervtis  Acujiicus , or  Portio  Mollis ; 
and  the  Cotnmunicam  Faciei,  or  Portio  Dura. 

The  Portio  Mollis,  is  the  fofteft  of  the  Nerves,  excepting 
the  Olfaftory. 

It  arifes  by  tranfverfe  Medullary  Striae  from  the  anterior 
part  of  the  Fourth  Ventricle,  and  is  feparated  from  its  fellow  of 
the  oppofi  e fide  only  by  the  Crena  of  the  Calamus  Scriptonus. 

The  Striae,  tuining  round  the  Medulla  Oblongata,  apply 
themi'elves  to  the  Tuber  Annulare,  from  which  they  receive  an 
addition  of  fubltance,  and  then  get  to  the  hde  of  the  Portia 
Dura. 

The  Portio  Dura,  fometimes  alfo  called  Syjnpatbeticus  Mi- 
nor, arifes  from  that  part  of  the  Brain  which  is  common  to  the 
Pun;  Varolii,  Crura  Cerebelli,  and  Medulla  Oblongata  ; and 
at  its  origin,  is  fituated  upon  the  inner  fide  of  the  Portio  Mol- 
lis. 

Between  the  origin  of  the  Portio  Dura  and  Trunk  of  the  Por- 
tio Mollis,  a fmail  Nerve  arifes,  termed  by.  Wrisberg,  Portio 
Media  inter  P.  Duram  et  P.  Mollem. . 

It  comes  off  by  rn.nute  Fibrillae,  which  foon  unite  into  a 
Trunk,  from  the  pofierior  pari  of  the  Pons  Varolii,  or  from 
the  adjoining  part  of  the  M Julia  Oblongata,  and  is  an  Accelfory 
Nerve  of  the  Portio  Dura. 

The  Port  o Dura,  conliderably  fmaller  than  the  P.  Mollis, 
gets  into  the  Meatu  - Aud  tonus  Interims,  and  is  there  lodged 
in  a kind  of  half-lheath,  formed  by  that  Nerve,  to  which  it  is 
connefted  by  fine  Cellular  Subftance  ; the  Dura  Mater,  which 
lines  the  Palfage,  giving  here  a general  Covering  to  both  Nerves. 

Portio  Mollis.— The  Portio  Mollis  is  formed  of  two  Faf- 
ciculi,  nearly  of  equal  fize,  one  of  which  belongs  to  the  Cochlea, 
the  other  to  the  Veifible  and  Semicircular  Canals. 

Each  of  thefe  Fafciculi  pafies  by  numberlefs  Fibrills  through 
the  Cribriform  Plate  in  the  bottom  of  the  Meatus  Auditorius  lu- 
ternus,  to  the  inner  parts  of  the  Labyrinth. 

Vol.  II.  U 2 


234 


TheFibrillae  deftined  for  the  Cochlea  go  through  the  Holes  in 
the  fides  of  the  Modiolus. 

Some  pafs  between  the  Plates  which  form  the  Septa  of  the  Gy- 
ri  ; others  go  through  Holes  between  the  Offeous  Plates  of  the 
Lamina  Spiralis  ; but  by  much  the  greateft  number  perforate  the 
ftdes  of  the  Modiolus,  between  the  Septum  of  the  Gyri  and  the 
Lamina  Spiralis. 

The  larger  F brills  run  upon  the  Membrane  covering  the  La- 
mina Spiral i s ; while  the  fmaller  go  from  the  Modiolus,  between 
the  Olfeotis  Septa  and  on  the  inner  (ides  of  the  Gyri,  to  be  dif- 
perfed  upon  the  Membrane  lining  them. 

The  remaining  Fibrillae  perforate  the  Plate  common  to  the  Mo- 
diolus and  Infundibulum,  and  vanifh  upon  the  laft  half-turn  of 
the  Lamina  Spiralis  and  the  Cupola  of  the  Cochlea. 

Upon  the  Ofieous  part  of  the  Lamina  Spiralis,  the  Nerves  have 
the  common  appearance  ; but  upon  the  Membranous  Portion, 
they  are  of  the  colour  of  the  Retina  of  the  Eye. 

In  the  whole  of  their  courfe  upon  the  Lamina  Spiralis,  they 
form  a real  Retina  ; though  the  reticulated  ftrufture  becomes 
much  lefs  apparent  upon  the  outer  part  of  this  Lamina,  and  upon 
the  continuation  of  the. Membrane  lining  the  Gyri, — the  Nerves 
feeming  to  terminate  in  a femipellucid  Pulpy  Membrane  refem- 
bling  the  Retina  of  the  Eye. 

The  Membrane  upon  which  the  Nerves  are  expanded,  is  but 
flightly  conne£ted  to  the  Periofteum  which  lines  the  inner  fide 
of  the  Cochlea,  and  which,  though  thin,  may  be  readily  percei- 
ved, being  painted  with  Blood-vefTels  ,— nor  does  it  differ  from 
the  Periofteum  lining  the  Tympanum. — See  Dr.  Monro’s  'Trea- 
tife  on  the  Ear. 

The  Fafcicuius  which  belongs  to  the  Veftible  and  Semicircular 
Canals,  forms  at  full  a Plexus,  then  a Gangliform  Enlargement, 
previous  to  its  entrance  into  the  Labyrinth. 

The  Neives  which  belong  to  the  Veftible  and  Semicircular  Ca- 
nals pafs  through  the  Macula  Cribrofa,  or  Holes  fubdivided  into 
fmaller  Holes  by  Cribriform  Plates  in  the  bottom  of  the  Meatus 
Auditorius  Internus. 

Of  thefe  Branches,  fmall  Filaments  pafs  through  the  Macula 
Cribrofa  in  the  Inferior  Foffula  of  the  Meatus  Auditorius  Inter- 
nus, to  the  Alveus  Communis  or  Sacculus  Vcftibuli. 

A fmall  Branch  goes  through  another  Cribiiform  Hole  in  the 
Inferior  Foffula,  to  the  Ampulla  of  the  Pofteiior  Membranace- 
ous Semuircular  Canal. 

A Branch  larger  than  any  of  the  former,  enters  the  Pofterior 
Hole  in  the  upper  Foffula  of  the  Meatus  Internus,  to  be  dil'perfed 
,upon  the  Ampullae  of  the  Superior  and  Exterior  Membranaceous 
Canals. 

The  Nerves,  after  reaching  the  Sacculus  Veftibnli  and  the 
different  Ampullae,  are  fpread  out  upon  them,  as  in  the  Cochlea, 


235 


in  the  form  of  a Net-work,  the  Fibres  of  which,  by  degrees  be- 
coming pellucid,  dilappear  upon  the  beginning  uf  the  Membra- 
naceous Canals. 

Portio  Dura.— The  Portio  Dura  feparates  from  the  Portio 
Moilis,  at  the  bottom  of  the  Meatus  Auditorius  Internus,  and 
enters  the  Canalis  or  AquaduBus  Fallopii,  by  the  anterioi  Hole 
in  the  upper  FolTula  at  the  bottom  of  the  Meatus. 

After  getting  into  the  Canal,  it  receives  the  retrograde  Nerve 
from  the  Second  Branch  of  the  Fifth  Pair,  which  enters  by  the 
Foramen  Innominatum  on  the  fore-fide  of  the  Pars  Petrofa. 

It  lends  Twigs  through  Foramina  in  the  Tides  of  the  Aquedufl, 
to  the  Maltoid  Cells  and  to  the  Mufele  of  the  Stapes. 

A little  before  its  exit  from  the  AqueduSt  in  the  Adult,  but 
at  the  outer  end  of  it  in  the  Foetus,  it  gives  off  a reflected  Branch, 
termed  Chorda  Tympani,  which  palfes  between  the  long  Pro- 
celfes  of  the  Malleus  and  Incus,  and  over  the  Membrana  Tym- 
pani. 

The  Chorda  Tympani  goes  afterwards  in  a Filfure  at  the 
outlide  of  the  Euftachian  Tube,  and  joins  the  Lingual  Branch 
of  the  Fifth  Pair,  foon  after  that  Nerve  has  got  out  of  the  Cra- 
nium. 

In  its  pafl'age,  it  fupplies  the  Mufcles  of  the  Malleus,  and  the 
Membranes,  See.  of  the  Tympanum. 

"The  Portio  Dura  afterwards  palfes  out  of  the  Aqueduft  by 
the  Foramen  Stylo-maftoideum,  and  is  at  firft  lodged  deep,  being 
lituated  in  a hollow  behind  the  Parotid  Gland. 

Herttjt  gives  a fmall  Occipital  Branch,  which  fends  Twigs  to 
the  back  part  of  the  Ear,  and  terminates  in  the  Oblique  Mufcles 
of  the  Head. 

It  fends  a Branch  to  the  Digaltric,  and  another  to  the  Stylo- 
hyoid Mufele  ; gives  off  a Filament  which  joins  the  Auricular 
Branch  of  the  Inferior  Maxillary  Nerve,  and  goes  to  the  fore- 
part of  the  Ear;  and  is  connect'd  by  another  fmall  Filament  at 
the  under  part  of  the  Ear,  wuh  Branches  of  the  Sympathetic 
Nerve  which  run  along  the  External  Carotid  Artery. 

It  alfo  furnfhes  Filaments  to  the  Parotid  Gland,  and  then  per- 
forates it,  dividing  into  large  Branches,  which  join,  feparate,  and 
rejoin,  different  times,  on  the  fide  of  the  Face. 

This  Plexus  is  expanded  in  fuch  a manner  as  to  con ftitute  what 
has  been  called  by  fome  the  Pes  Anferinus,  and  is  divided  into 
the  following  fets  of  Branches,  viz. 

The  Temporal  Branches , which  afeend  upon  the  fide  of  the 
Head,  to  be  dilfributed  upon  the  Temple  ; fome  running  over, 
others  under.. he  Branches  of  the  Temporal  Artery,  and  forming 
feveral  joinings  with  the  Frontal  Branches  of  the  firft  part  of  the 
Fifth  Pair  of  Nerves  : 

The  Superio - Facial  Branches,  which  are  difperfed  upon  the 
Orbicularis  Ocuii  Mufele,  and  the  parts  in  general  about  the 


236 


outer  angle  of  the  Eye,  communicating  in  various  places  above 
and  below  the  Orbit,  with  the  firft  and  fecond  Branches  of  the 
Fifth  Pair  : 

The  Middle  Facial  Branch,  or  the  Great  Facial  Nerve,  which 
runs  acrufs  the  Maffeter  Mufcle,  and  divides  into  many 
Branches,  to  be  difperfed  upon  the  Cheek,  and  fide  of  the  Nol'e 
and  Lips. 

They  are  connected  with  the  Branches  of  the  Superior  Facial, 
and  near  the  coiner  of  the  Mouth,  with  others  of  the  fecond 
and  third  parts  of  the  Fifth  Pair.  They  have  likewife  fome 
communications  with  deep  Branches  of  thefe  two  Nerves  which 
pafs  outwards  between  the  Maffeter  and  Buccinator  Mufcles. 

The  Inferior  Facial  Branches,  which  pioceed  along  the  fide  of 
the  under  Jaw,  to  be  difperfed  upon  the  parts  covering  it,  and  up- 
on the  Under  Lip  ; and  connefl  themfeives  with  fome  of  the 
Middle  Facial  Branches,  and  with  others  belonging  to  the  third 
part  of  the  Fifth  Pair  : 

The  Defcending,  or  Subcutaneous  Cervical  Branches,  fome  of 
which  run  forwards  under  the  Lower  Jaw,  and  others  down- 
wards, near  the  External  Jugular  Vein,  to  the  Superficial  Muf- 
cles, and  to  the  Integuments  at  the  fide  and  upper  part  of  the 
Neck,  where  they  form  communicatioHs  with  the  Infeiior  Facial 
Branches,  and  with  diffeicnt  Branches  of  the  upper  Spinal  Cer- 
vical Nerves. 

The  Eighth  Pair  arifcs  from  the  Medulla  Oblongata,  at 
the  f.des  of  the  Bales  oi  the  Corpora  Olivaria,  and  confilt  in  each 
fide,  of  the  Nervus  Gloffo  phtryngeus,  and  Pars  Vaga. 

The  Glosso-PharyNglus  is  the  IlnallerAf  the  two,  being 
only  a little  fupeiior  in  lize  to  one  of  the  Nerves  of  the  Fourth 
Pair. 

The  Pars  Vaga  comes  off  immediately  under  the  former,  and 
is  competed  of  l'everal  feparated  Fafciculi,  which  are  foon  col- 
lefled  itno  a iingie  Cord. 

The  two  Nerves,  paffing  outwards,  go  through  the  Bafe  of  the 
Cranium,  immediately  befoie  the  end  of  the  Lateral  Sinus,  by 
the  Hole  common  to  the  Occipital  and  Temporal  Bone,  and  are 
feparated  from  each  other  and  from  the  Sinus  by  fmall  Proceffes 
of  the  Dura  Mater. 

The  Glojfo  P haryngeus,  termed  alfo  Lingualis  Lateralis,  upon 
its  exit  from  che  Ciani"m.  lends  a Branch  backwards,  which 
joins  the  Digaftric  Branch  of  the  • oitiu  Dura. 

A little  lower,  >t  gives  off  Branches,  which,  with  others  from 
the  Pharyngeal  Branch  of  the  Eighth  Pa  r,  and  from  the  Great 
Sympathetic  Nerve,  Wm  a Plexus  which  embraces  the  Internal 
Carotid  Artery,  and  afterwards  fends  Branches  along  the  Caro- 
tis  Communis  to  the  Heart. 

Still  lower,  it  gives  Branches  which  communicate  with  others 
belonging  to  the  Pharyngeal  Nerve,  and  go  to  the  upper  part  of 
the  Pharynx  arid  to  the  Stylo-Pharyngeus  Muffle. 


237 


The  Gloffo-Pharyngeus,  after  fending  a Twig  or  two  to  the 
Tonfil,  to  the  upper  part  of  the  Pharynx,  and  Membrane  of  the 
Epiglottis,  divides  into  many  Branches,  which  run  partly  to  the 
margin  and  partly  to  the  middle  of  the  root  of  the  Tongue,  fup- 
plying,  efpecially,  the  Papillae  Majores  and  the  parts  in  their 
neighbourhood. 

The  Pars  Faga,— upon  emerging  from  the  Cranium,  frequent- 
ly becomes  a little  increafed  in  diameter  fir  about  an  inch  down- 
wards ; forming  what  fome  authors  have  termed  its  Ganglifortn 
Enlargement. 

It  defcends  in  the  Neck  at  the  outer  and  back-part  of  the 
common  Carotid  Artery,  to  which  it  is  elolely  united,  being  in- 
cluded along  with  it  in  the  fame  common  (heath  of  Cellular  Sub- 
ftance. 

At  the  upper  part  of  the  Neck,  it  tranfmits  a Branch  to  the 
Pharynx  ; and  immediately  afterwards,  a large  one  to  the 
Larynx  ; and  near  the  top  of  the  Thorax,  it  fends  a Filament, 
and  fometimes  two,  to  the  Heart. 

The  Pharyngeus, — chiefly  formed  by  the  Pars  Vaga,  but  partly 
alfo  by  a Branch  from  the  AccefTonus,  is  afterwards  joined  by 
Branches  from  the  Gloffo-Pharyngeus,  and  defcends  obliquely 
over  the  Internal  Carotid  Artery. 

Near  the  origin  of  this  Artery,  it  fends  Filaments  which  join 
others  from  the  upper  part  of  the  Great  Sympathetic,  and  creep 
along  the  Common  Carotid,  to  be  united  with  the  Carotid  Ar- 
tery. 

Upon  the  middle  of  the»»Pharynx,  it  expands  into  a Gangli- 
form  Plexus,  from  which  many  fatal  1 Branches  are  fent  ou.,  to 
be  dillributed  upon  the  three  Conftrififors  of  the  correfponding 
fide  of  the  Pharynx  ; one  or  two  Filaments  uniting  ab  ve  with 
the  Gloffo-Pharyngeus, and  others  below  with  the  Laryngeus  Su- 
perior. 

The  Laryngeus  Superior, — defcends  obliquely  forwaids  be- 
tween the  Caiotid  Arteries  and  Pharynx  ; and  behind  the  origin 
of  the  Carotids,  is  divided  into  a large  Internal  or  Superior,  and 
a final!  External  or  Inferior  Branch. 

The  Internal  Branch  paffes  forwards  between  the  Os  Hyoides 
and  Superior  Cornu  of  the  Thyroid  Cartilage. 

It  divides  into  numerous  Branches,  fome  of  which  go  to  the 
Arytenoid  Gland,  and  to  the  Oblique  and  Tranfverfe  Arytenoid 
Mufcles,  and  others  to  the  Glandular  Membrane  of  the  Epiglot- 
tis ; while  the  greater  number  and  the  lar  elf  of  thei'e  Branches 
are  dtiperfed  upon  the  Glandular  Membrane  lining  the  upper 
portion  of  the  Larynx  and  parts  adjacent. 

The  External  Branch,— -which  Scarpa  confiders  as  more  pro- 
perly termed  Pbaryngo  Laryngeus, — is  originally  compofed  of  a 
Branch  from  the  Internal  Laryngeal,  and  another  from  the  Great 


233 


Sympathetic  ; and  is  conneXed  by  a Filament  to  the  Pharyngeal, 
and  i'ometimes  alfu  by  one  to  the  Internal  Laryngeal  Nerve. 

It  imparts  Twigs  to  ih  Middle  and  Lower  ConftriXors  of  the 
Pharynx,  and  afterwards  terminates  in  the  fhyroid  Gland  and 
inner  part  of  the  Larynx. 

The  Filament,  lent  from  the  Pars  V.tga  at  the  bottom  of  the 
Neck,  joins  the  Gieat  Cardiac  Bianeh  of  the  Sympathetic  Nerve 
in  the  upper  part  of  the  Thorax,  to  be  difperfed  upon  the  Heart, 

The  Ninth  Pair, — frequently  termed  Linguales,  and  fome- 
times  Linguales  MeJii ,■ — arile  from  the  under  and  lateral  parts  of 
the  Coipora  Pyram  dtlia,  on  the  foie  fide  of  the  Medulla  Ob- 
longata, by  numerous  Filaments  which  are  culleXcd  into  Faf- 
ciculi. 

They  pafs  out  at  the  Superioi  Cond  . 1 rid  Foramina  of  the  Oc- 
c'pital  Bone,  after  which  they  adhere,  for  fome  way,  to  the 
Eighth  Pair,  by  Cellular  Spbdtnce. 

A little  below  the  Cranium,  each  of  the  Trunks  of  tills  Pair 
of  Nerves  s conjoined  by  a crofs  Branch  with  the  Suboccip  tal 
Nerve,  or  with  an  Arch  which  conneXs  that  Nerve  and  the  Full 
Cervical  together. 

The  Trunk  then  depends  between  the  Internal  Jugular  Vein 
and  Internal  Carotid  Artery,  and  at  the  toot  of  the  Occipital  Ar- 
tery erodes  over  bo'b  Carotids  to  its  place  of  deft  nation. 

Where  it  begins  to  crofs  oyer  the  Carotid?,  it  fends  down  a 
Branchof  considerable  ftze,  termed  Defcend.ens  Noni. 

Til  Defcendens  Noni  paffes  down  a certain  length  along'  with 
the  common  Catolul  Artery,  and,  in  its  courfe,  furn  Ihes 
Branches  to  the  upper  ends  of  the  Omo-hyoid  and  Sterno-thyroid 
MnlcJes,  after  which  it  unites  with  Branches  fr.  m the  Fit  ft  and 
Second,  ar.d  with  (’mail  Filaments  from  the  Second  and  Third 
Cetvical  Nerves,  forming  an  Arch,  from  which  I.  hg  and  (lender 
Twigs  go  to  the  under  portions  of  the  Sterno-thyroid,  and  to  the 
Omo-hyo  d and  Sterno-hyoid  Mufcles. 

The  Ninth  Pair  paffes  afterwards  behind  the  Facial  Trunk 
and  Temporal  Veins,  or  the  Trunk  formed  by  thefe,  and  over  the 
root  of  the  Facia!  Artery,— fending  a Nervous  Twig  to  the  Hyo- 
thyioid  Mufcle. 

Upon  the  Hyo-gloflus  Mufcle,  the  Trunk  of  the  Nerve  is 
fpread  into  a great  number  of  Branches,  which  go  to  the  middle 
of  the  Tongue,  and  terminate  chiefly  in  its  Flcfhy  parts  ; a Twig 
extending  as  far  as  the  Genio-hyoid  Mufcle,  and  two  or  fome- 
times  only  one  Filament  anaftomofing  fvith  the  Lingual  Branch 
of  the  Fifth  Pair. 

The  Great  Sympathetic  Nerve, — obtaining  its  name 
from  its  numerous  Connexions  with  moft  of  the  other  Nerves  of 
the  Body,- — ;s  either  formed  originally  by  the  reflected  Branch 
from  the  fecond  of  the  Fifth  Pair,  and  by  one  or  two  and  fome- 
times  three  fmall  Filaments,  fent  down  from  the  Sixth  Pair  while 


239 


in  the  Cavernous  Sinus  ; or,  according  to  the  opinion  of  feme 
Authors,  the  Sympathetic  fends  off  thefe  fmall  Nerves  to  join  the 
Fifth  and  Sixth  Pairs. 

Upon  the  Surface  of  the  Internal  Carotid  Aitery,  while  in  the 
Carotic  Canal,  the  Branches  of  the  Fifth  and  Sixth  Pairs  and 
Great  Sympathetic  miking  this  connexion,  are  pal,  y and  tender, 
and  foim  a Plexus  which  furrounds  the  Carotid,  and  from  which 
the  Trunk  of  the  Sympathetic  is  mod  frequently  confidered  as 
being  fent  out. 

At  er  efcaping  from  the  Carotic  Canal,  the  Trunk  which  is 
of  fmall  fze,  is  clolely  connefied,  for  a fhort  fpace,  with  the 
Trunks  of  the  Eighth  and  Ninth  Pairs;  and,  fepara.ing  from 
thefe,  it  expands  into  a large  Ganglion, — termed  Ganglion  Cer-vi- 
cale  Supeiius, — of  a long  oval  form,  and  licuated  oppolite  to  the- 
Second  Cervical  Vertebra. 

From  this  Ganglion,  the  Nerve  comes  out  very  little  increafed 
in  fize, — and  delcends  on  the  anterior  Vertebral  Mufcles  of  the 
Neck, — behind  the  Eighth  Pair  of  Nerves,  with  which,  and 
with  the  Carotid  Ai  tery,  it  is  connefled  by  a Sheath  of  Cellular 
Subftance. 

At  the  under  part  of  the  Neck,  and  nearly  where  the  Inferior 
Laryngeal  Artery  turns  over  towards  the  Larynx,  ihe  Sympa- 
thetic form,  another  Ganglion,  termed  by  fume  Authors  Cer<ui- 
c ale  Medium  and  by  others  Cernjicale  lnferius. 

The  Ganglion  Medium  is  fomewhat  nmilar  in  fhape  and  fize  to 
the  Ganglion  Superius  ; though  it  varies  coniideiably  in  thefe 
rel'pe£ts  in  diffeient  Subjefts. 

From  this  Ganglion,  principal  Branches  are  fent  down,  one  of 
which,  larger  than  the  reft,  and  considered  as  the  continuaiion  of 
the  Trunk,  turns  outwards  between  the  Inferior  Laryngeal  and 
Vertebral  Arteries  to  another  Ganglion. 

This  third  Ganglion, — is  placed  at  the  head  of  the  firft  Rib, 
and  is  termed  by  lome  Authors  Ganglion  Cer-uicale  lnferius , or 
Imum,  while  others  coniider  it  as  the  firft  of  the  Thoracic  Gan- 
glia^ 

The  Cervical  part  of  the  Great  Sympathetic  is  connefted  with 
other  Nerves,  and  difperfed  upon  diffeient  parts  by  the  following 
Branches,  viz. 

One  or  two  fhort,  but  thick  Branches,  which  corineS  the  be- 
ginning of  the  Superior  Ganglion  with  the  root  of  the  Subocci- 
'pital  Nerve  : 

Oae  or  two  Pulpy  Nerves,  which  run  forwards  behind  the  In- 
ternal Carotid  Artery,  and  divide  into  many  others.  Thele,  to- 
gether w.th  Filaments  from  the  Gloffo-pharyngeus,  »>rm  a 
Plexus  which  fends  Branches  to  the  Ganglform  Expanlion  of  the 
Pharyngeus,  and  afterwards  embiaces.  the  external  Carotid 
Artery,  fending  PJexufes  of  Filaments  along  its  different 
Branches  : 


240 


One  or  two  other  Toft  Nerves,  going  behind  the  Internal  Caro- 
tid, and  with  a Branch  of  the  Laryngeus  Interims  of  the  Eighth 
Pair,  forming  the  Laryngeus  Externus  : 

Thick  (hort  Roots  connecting  the  Firit,  or  Conjugation  of  the 
Firit  and  Second  Cervicals,  with  the  fuperior  Ganglion  of  the 
Spmpathetic  Nerve. 

From  the  Superior  Ganglion  alfo,  are  fent  offfmall  Branches, 
which  uniting  with  Filaments  from  the  Laryngeus  Superior, 
form  the  Rumus  C.ardiacus  Supremus,  or  Superficial is  Cordis. 

The  Superficial  Cardiac  Nernje  of  the  Sympathetic,  in  the 
Right  Side,  d vides  into  Branches  at  the  bottom  of  the  Neck, 
which  fend  a Filament  or  two  along  the  Inferior  Laryngeal  Ar- 
tery to  the  Thyroid  Gland  and  afterwards  unite  with  the  Superfi- 
cial Cardiac  Nerve  of  the  Eighth  Pair  before  the  Subclavian  Ar- 
tery, and  with  the  Laryngeal  Nerve  behind  it.— In  the  left  fide, 
it  terminates  in  the  Cardiac  Plexus  of  Nerves. 

From  the  Second,  Third,  and  Fourth  Cervical  Nerves,  an 
equal  number  of  Cords  defcend  behind  the  Scaleni  and  ReXus 
Major  Mufcle,  to  the  middle  Ganglion  of  the  Great  Sympa- 
thetic. 

From  the  oppofite  fide  of  the  Ganglion,  Branches  are  fent 
down,  which  join  and  form  the  Ner-uous  Magnus  Projundus  ; 
others  are  fixed  to  the  Superficial  Cardiac  and  to  the  Recurrent  of 
the  Eighth  Pair  the  relt  go  partly  over  and  partly  beh  nd  the 
Subclavian  Artery,  to  the  Inferior  Cervical,  and  to  the  firft 
Thoracic  Ganglion. 

Nervi  Accessorii  ad  Par  Octavom, — The  Acceffory 
Nerves  arile  by  fmall  Filaments  from  the  lateral  Parts  of  the 
Medulla  Oblongata  and  upper  portion  of  the  Spinal  Marrow. 

The  Filaments  from  the  Spinal  Marrow  come  off  between  the 
anterior  and  polterior  Bundies  of  the  Cervical  Nerves, — the  firft 
of  them  frequently  extending  as  far  as  the  /pace  between  the 
Sixth  and  Seventh  Pairs. 

The  different  Filaments  unite  by  degrees  into  their  refpeXive 
Trunks,  and  often  have  connexions  while  within  the  Dura 
Mater,  with  one  or  two  of  the  Bundles  of  the  upppermoll  Spinal 
Nerves. 

The  Trunk  of  the  Nerve  paffes  out,  on  each  fide  of  the  Cra- 
nium, in  company  with  the  Nerve  of  the  Eighth  Pair;  but  forms 
no  part  of  that  Nerve,  being  included  in  its  own  peculiar  Sheath 
received  from  the  Dura  Mater. 

After  perforating  the  Cranium,  it  feparates  from  the  Eighth, 
and  defcemls  obliquely  outwards  through  the  Sterno-maftoid 
Mufcle  to  the  Shoulder. 

At  its  exit,  it  fends  off  a Branch,  termed  by  fome  Ramus  Mi- 
nor, (the  Trunk  itf'elf  being  then  called  Ramus  Major),  which 
aflifts  in  forming  the  Pharyngeal  Nerve  ; and  gives  another, 


241 


(mailer  than  the  former,  to  be  conne&ed  to  the  Pars  Vaga  of  the 
Eighth  Pair. 

At  the  rore-part  of  the  Sterno-maftoid  Mufcle,  it  is  joined  by 
an  Arch  to  the  Suboccipital,  and  frequently  by  another  to  the 
Firft  Cervical  Nerve. 

In  its  paffage  through  the  Sterno-maftoideus,  it  fends  feveral 
Branches  to  the  fubftance  of  that  Mufcle,  and  terminates  at 
length  in  the  Trapezius. 


.OOOOOOOO -.K-OOOOOOOO' 


SPINAL  MARROW , 

AND 

ORIGIN  OF  THE  SPINAL  NERVES. 


THE  Spinal  Marrow  is  the  continuation  of  the  Medulla 
Oblongata,  and  obtains  its  name  from  being  contained  in  the 
Olfeous  Canal  of  the  Spine. 

It  is  inverted  by  the  fame  Membranes  which  cover  the  Brain, 
and  has  an  additional  partial  Involucrum  from  the  Ligamentous 
Membrane  which  lines  the  Bodies  of  the  Vertebrae,  and  which 
has  been  already  taken  notice  of  in  the  defcription  of  the  Liga- 
ments. 

On  the  inner  fide  of  the  Ligamentous  Lining,  the  Dura  Mater 
is  fituated,  which  paffes  out  of  the  Cranium  b^'  the  Foramen 
Magnum  Occipitis,  and  forms  a Cylindrical  Sheath  which  loofe- 
ly  envelopes  the  Spinal  Marrow,  and  extends  as  far  as  the  Os 
Sacrum. 

It  is  more  elaftic  than  the  Dura  Mater  of  the  Brain,  and  there 
by  admits  more  readily  of  the  different  motions  of  the  Spine. 

At  its  egrefs  from  the  Cranium,  it  is  int  imately  connefled  to 
the  beginning  of  the  above-mentioned  common  Ligamentous 
Lining,  and  is  alfo  united  with  the  Pericranium  at  the  edge  of 
the  Foramen  Magnum  of  the  Occipital  Bone. 

Below  the  Firft  Vertebra  of  the  Neck  this  inornate  connexion 
between  the  Dura  Mater  and  inner  Ligament  of  the  Vertebrae  is 
difcontinued  ; a Celiular  Fatty,  and  Slimy  Subjiance,  which  fur- 

Vol.  II.  X 


242 


rounds  the  Dura  Mater  throughout  the  reft  of  the  Canal,  being 
interpoi'ed  between  the  Membrane  and  the  Ligament. 

The  Dura  Mater  is  only  in  coniadt  with  the  Tunica  Arachnoi- 
dea,  and  this  alfo  only  in  contatt  with  the  Pia  Mater,  and  lying 
lo  loolefy  over  it  as  to  be  feparated  (torn  it  with  facility  through 
the  whole  length  of  the  Spine. 

The  Sj  inal  Marrow,  rke  the  Brain,  confifts  of  a cortical  and 
Medullary  Subftnnce,  but  d'ffers  in  this  rel’peft,  that  the  Cineri- 
tious  Matter  is  placed  within  the  other. 

Upon  the  Sutface  of  the  Spinal  Marrow,  while  lying  in  its 
natural  fituation,  many  tranfverfe  Wrinkles  or  Folds  are  ob- 
ierved,  which  allow  it  to  be  extended  in  the  motions  of  the  Ver- 
tebias. 

It  is  a little  flattened  on  its  anterior  and  pofterior  Surfaces,  and 
is  larger  near  the  under  part  of  the  Neck,  and  at  the  top  of  the 
Loins  where  the  great  Nerves  of  the  Extremities  are  fent  off,  than 
in  the  other  parts  of  the  Spine. 

It  is  divided  into  two  lateral  Portions  or  Cords,  which  are  fepa- 
rated from  each  other  externally  by  an  anterior  and  pofterior  Fif- 
fure  continued  from  the  Medulla  Oblongata;  and  each  of  the. 
lateral  Portions  is  in  fome  meafure  fubdivided  bv  a fuperficial 
Furrow  into  a larger  anterior  and  f'mall  pofterior  Cord. 

The  lateral  Portions  are  firmly  united  together  by  fine  Cellu- 
lar Subftance,  but  may  be  feparated  from  each  other  before  as 
well  as  behind, — without  lacerating  either, — to  near  their  mid- 
dle, where  they  are  conne£fed  by  a Layer  of  Cineritious  Mat- 
ter which  paftbs  from  the  one  Cord  into  the  other. 

When  the  Medulla  Spinalis  is  divided  tranfverfely,  the  Cine- 
ritious Subftance  is  obferved  to  have  a Cruciform  appearance, 
correfponding  with  the  Cords  of  which  it  is  compofed. 

The  Body  of  the  Spinal  Marrow  defeends  as  far  as  the  Second 
Vertebra  of  the  Loins,  and  terminates  there  by  a Conical  point, 
which  is  concealed  by  Fafculi  of  Nerves. 

Each  of  the  lateral  poitions  of  the  Spinal  Marrow  fends  off 
from  its  anterior  and  pofterior  parts,  flat  Fafciculi  of  Nervous 
Filaments,  wltich  are  placed  oppofite  their  fellows  on  the  other 
fide.  ^ 

Several  of  the  Fafciculi  of  the  Cervical  Nerves  detach  Fila- 
ments to  thole  immediately  above  or  below  them  ; and  the  fame 
thing  is  occafionally  obferved  of  fome  of  the  Bundles  of  Dorl'al 
Nerves. 

The  anterior  and  pofterior  Fafciculi  perforate  the  Dura  Mater, 
from  the  inner  part  of  which  each  Fafciculus  is  furnifhed  with  a 
proper  Sheath,  and  is  continued  within  it,  the  Sheaths  conne£Kd 
by  Cellular  Subftance  only,  till  they  get  between  the  Vertebrae. 

Between  the  anterior  and  pofterior  Fafciculi  or  Spinal  Neives, 
and  between  the  Tunica  Arathnoidea  and  Pia  Mater,  a fmall 
Ligamentous  Cord  termed  Ligamentum  Dcnticulatum , is  fituated, 


245 


which  is  attached  to  the  Dura  Mater,  where  that  Membrane 
comes  out  from  tile  Cranium  and  accompanies  the  Spinal  Mar- 
row to  its  inferior  extremity. 

It  adheres  ' >y  Cellular  Subllance  to  the  Pia  Mater,  and  fends 
off  f orn  its  oppofite  fide  lYnall  Cords,  in  the  form  of  Denticuli , 
which  carry  the  Tunica  Arachnoidea  along  with  them,  and  run- 
ning more  or  iefs  in  a tranfverfe  d:re£Lon,  are  fixed,  each  by 
minute  Fibres  to  the  Dura  Mater,  in  the  Interflices  of  theFafci- 
culi. 

The  Ligamentum  Denticulatum  of  the  oppofite  fides  incorpo- 
rate with  he  Pia  Mater  at  the  inferior  extremity,  or  Conical  point 
of  the  Spinal  Mairow,  and  forma  Ligamentous  Filament  which 
perforates  the  under  end  of  the  Dura  Mater,  and  is  fixed  by 
fimail  Fibres  to  the  Membranes  covering  the  Os  Coccygis,  in 
the  manner  the  Denticuli  are  fixed  to  the  Dura  Mater. 

It  was  termed  by  Come  Authors  Ligamentum  Pia:  Matris.  It 
was  considered  by  the  Ancients  as  the  Fortieth  Pair  of  Nerves, 
and  was  alio  called  Ner-vus  Imparus  Sacrus. 

It  affifts  in  preventing  the  Spinal  Marrow  and  the  tender  origin 
of  the  Nerves  from  being  overftretched. 

Having  got  between  the  Vertebrae,  each  of  the  pofterior  Bun- 
dles forms  a Ganglion,  from  the  oppofite  end  of  which  a Nerve 
comes  out,  and  is  immediately  joined  by  the  anterior  Bundle, 
thus  conftituting  the  beginnings  of  the  Trunks  of  the  Spinal 
Nerves. 

The  Nervous  Cords  fent  out  from  the  Spinal  Marrow,  after  re- 
ceiving their  coverings  from  the  Dura  Mater,  become  confidera- 
biy  larger  than  the  Fafciculi  which  form  them  ; as  has  been 
already  obferved  in  the  general  defcription  of  the  Nerves. 

As  foon  as  the  Spinal  Nerves  emerge  from  between  the  Verte- 
brae, each  lends  Branches  backwards  to  theMufcles  near  the  Spine, 
and  others  forwards  to  join  the  Great  Sympathetic  Nerve,  while 
the  Trunk  is  continued  outwards  to  its  place  of  deftlnation. 

The  Spinal  Nerves  are  diftingui fned  on  each  fide,  by  numbers, 
aceoiding  to  the  Bones  under  which  they  pafs  ; Thirty  Pairs  are 
meft  commonly  enumerated. — One  going  under  the  Head,  and 
termed  Suboccipttal — Seven  p fling  under  the  Vertebra;  of  the 
Neck  ; — Twelve  under  the  Dorfal  ; — Five  under  the  Lumbar  Ver- 
tebrae ; an  , — Five  under  the  pieces  which  originally  compofed 
the  O,  Sacrum. 

The  Fafciculi  which  form  the  Cervical  Nerves  are  fhart,  run- 
ning nearly  in  a ftraight  direflion  from  their  origin  to  the  Inter- 
vertebral  Holes.  Thofe  which  form  the  Dorfal  Nerves  are  long- 
er than  the  former,  and  run  more  obliquely  downwards  ; and 
thofe  which  form  the  Lumbar  and  Sacral  Nerves  are  very  long  and 
run  Hill  more  obliquely  downwards,  till  at  length  the  undennoft 
ef  them  become  nearly  longitudinal. 


244 


The  fize  cf  the  Fafculi  correfponds  with  that  of  the  Nerves 
which  they  go  to  form. — The  Fafciculi  of  the  four  loweft  Cervi- 
cal and  fii  it  Dorfal,  are  large  and  broad,  giving  origin  to  the 
Gieat  Nerves  which  fupply  the  Superior  Extremity Thofe  of 
the  Back  are  much  more  [lender,  while  the  Fafciculi  of  the  Loins 
and  the  two  upper  Sacral  ones  are  of  great  fize,  to  form  the 
very  large  Nhrves  which  run  to  the  Lower  Extremity. 

The  Lumbar  and  Sacral  Fafciculi,  while  included  in  the  Dura 
Mater,  form  a Bundle  of  Cords,  termed  Cauda  Equina,  from 
the  relcmblance  it  has  to  the  Tail  of  a Horfe  ; efpecially  when 
the  FibrilTae  of  the  Nerv.es  are  unravelled  by  feparating  them  from 
each  other. 

The  Fafciculi  perforate  theDuia  Mater,  nearly  oppofite  to  the 
parts  where  they  pais  through  the  Vertebrae, — of  courfe  the 
Nerves  of  the  inferior  parts  of  the  Spinal  Marrow  emerge  from 
the  Spine,  confide!  ably  lower  than  their  different  origins. 

Blood-Vessels  of  the  Spinal  Marrow. — The  Arte- 
ries of  tlie  Spinal  Marrow  conlilt  of  Anterior  and  Pofterior  Spi- 
nal An  eries,  and  of  many  additional  Branches  communicating 
with  o.liers  from  the  adjacent  Vtlfels. 

The  Anterior  Spinal  arteries  arife,  one  on  each  fide,  from  the 
Vertebrals,  near  where  thel'e  join  to  form  the  Balilar  Artery. 

Upon  the  beginning  of  the  Spinal  Marrows  they  generally 
unite  into  a common  Trunk,  winch  defeends-  in  that  depreffion 
on  the  Anterior  Surface  of  the  Medulla,  whereby  it  is  diftin- 
guifhed  into  two  Lateral  Portions, — and  the  Artery  continues 
nearly  of  the  fame  fize  throughout,  in  confequence  of  additions 
it  receives  from  the  neighbouring  Arteries. 

In  the  Neck,  it  communicates  with  the  Vertebral  Thyroid,  and 
Cervical  Arteries,  by  Blanches  which  pafs  through  the  fame 
Holes  with  the  Nerves. 

In  the  Back,  it  receives  Branches  from  the  Intercoftal,  and  in 
the  Loins  from  the  Lumbar  Arteries;  all  of  which  alfio  go 
through  the  Intervertebral  Holes. 

It  terminates  at  the  under  end  of  the  Spinal  Marrow;  the 
Cauda  Equina  being  fupplied  by  Branches  from  the  Internal 
Iliac  Artery,  which  enter  through  the  anterior  and  pofterior 
Holes  of  the  Os  Sacrum. 

The  i ojlerior  Spinal  Arteries, — arife  commonly  from  the  infe- 
rior Arteries  of  the  Cerebellum,  and  frequently  from  the  Trunks 
of  the  Vertebral  Arteries  within  the  Cranium. 

They  are  equal  in  length  to  the  tormer  Artery,  but  confidera- 
bly  inferior  to  it  in  lize,  and  continue  feparate  through  the  whole 
of  the  r courfe. 

They  have  conftantly  a Serpentine  appearance,  and  foim  fre- 
quent Inofcul  tions  with  each  other,  and  with  Arteries,  the 
Branches  of  which  communicate  with  the  anterior  Spinal  Ar- 
tery. 


245 


The  Arteries  of  the  Spinal  Mirrow  are  divided  into  minute 
Branches,  which  are  difperfed  upon  its  fubftance,  upon  the  Mem- 
branes which  inclofe  it,  and  alfo  upon  the  fubftance  of  the  Verte- 
brae and  upon  the  origins  of  the  Nerves. 

The  Veins  of  the  Spinal  Marrow  accompany  their  Arteries, 
and  afterwards  terminate  in  the  Sinus  Venoii  of  the  Spine. 

The  Sinus  Venofi  conlift  of  one  on  each  fide,  which  runs  exte- 
rior to  the  Dura  Miter,  being  chiefly  lodged  in  the  Ligamen- 
tous Membrane  which  lines  the  fore  and  lateral  parts  of  the  Ver- 
tebral Canal. 

They  extend  from  the  Foramen  Magnum  of  the  Occipital 
Bone,  to  the  under  end  of  the  Os  Sacrum,  and  are  fo  irregular 
on  their  furface,  and  fo  much  divided  and  fubdivided  within  by 
the  openings  of  Veins,  as  in  many  parts  to  have  the  appearance 
of  Cells. 

At  the  different  Vertebrae,  they  are  conjoined  by  crofs  Branch- 
es, wnich  have  a Semilunar  form,  like  the  furface  of  the  Bones 
which  furround  them. 

They  communicate  at  their  Superior  extremity  with  the  Occi- 
pital and  Lateral  Sinufes,  and  lend  numberlel's  Branches  out- 
wards, wh  ch  open  into  the  Veins  the  Arteries  of  which  anafto- 
mofe  with  thofe  of  the  Spinal  Marrow. 

Nerves  of  the  Neck  and  Superior 
Extremity. 

Nervus  Accessorius. — The  AccefTory  Nerve  belongs  in 
fome  refpects  to  this  Clais  of  Nerves  ; — >ut  having  part  of  its 
origin  .ithin  the  Head,  and  from  its  palTing  out  with  one  of  the 
Cerebral  Nerves,  it  has  been  already  defer: bed  along  with  thefe. 

Suboccipital  Nerves. — Thefe  we.  e formerly  called  Tenth 
Fair  of  the  Head,  and  by  many  at  prelent  are  termed  Firfi  of  the 
Neck. 

They  arife,  on  each  fide,  from  the  beginning  of  the  Spinal 
Marr  .w,  by  an  Anterior  and  Potterin'  Fafciculus,  like  the  reii 
of  the  Spinal  Nerves  ; and,  like  thefe  alfo,  they  have  their  Gan- 
glia where  they  pafs  out  beiween  the  Bones. 

They  perforate  the  Dura  Mater  immediately  under  the  en- 
trance of  the  Vertebral  Arteries,  and  pafs  forwards  under  them, 
and  over  the  rranfverfe  Procefles  of  the  Atlas. 

They  afterwards  appear  in  the  fore-part  of  the  Neck,  and  are 
each  connected  above  by  an  Arch  to  the  root  of  the  Ninth  Pair, 
and  below  by  a ftmilar  Arch  to  he  Firft  Cervical  Nerve. 

Anteriorly,  they  are  joined  by  one  or  two  ihorl  Branches  to 
the  upper  Ganglia  oftheGreat  Sympathetic  Nerve. 

They  afterwards  divide  into  Branches,  which  are  diftributed 
upon  the  Reibi  and  Obliqui  Capitis,  and  upon  fome  of  the  Deep 
Extenfor  Mufcles  of  the  Head. 

Vol.  II,  X 2 


246 


The  First  Cervical  Nerve, — omes  out,  on  each  fide,  be- 
tween  :iie  Atlas  and  Second  V ...  i>r;,  f ihe  Neck,  and  immedi- 
ately fplits  nto  two  parts  j the  i it  of  which  palfe- forwa;  ds  un- 
der t ht  tranl'verl'e  Procefs  f he  Atlas.,  and  is  joined  by  an  Arch 
with  the  Nei  vus  Aeeelloi  ius.  and  by  Brandies  with  the  Ninth 
Pair:  it  is  alfo  roi, nieiSbed  by  a loft  Ganghform  pellucid  root  with 
tl.e  ppei  Gang!  n of  the  Symmithfe  ir  Nerve,  lending  a Branch 
downwards,  to  be  fixed  to  the  lecond  Cervical  rNerve,  and  alfo 
fmall  Branches  to  the  Mufcles  connected  with  the  fore  part  of 
the  Vep tbrte. 

The  othei,  which  is  the  principal  part,  goes  backwards,  and, 
after  fending  Blanches  to  the  Extenfor  Mufcles  of  the  Head  and 
Neck,  perforates  thele,  and  forms  the  Proper  Occipital  Nerve. 

The  Occipital  Nerve  afcends  upon  the  Head  with  the  Artery  of 
that  name,  and  terminates  upon  the  Mufcles  and  Integuments  on 
the  upper  and  back-part  of  the  Head;  fome  of  its  Filaments 
anaftpmofin.:  with  others  belonging  to  ihe  Fil'd  Branch  of  the 
Fifth,  and  Portio  Ultra  of  the  Seventh  Pair. 

The  Second  Cervical  Nerve, — fter  efcaping  from  be- 
tween the  Bones,  gives  off  a Branch,  which  perforates  the  Muf- 
cles connected  to  the  fore  and  lateial  parts  of  the  Vertebise,  and 
joins  the  middle  Ganglion  of  the  Sympathetic  Nerve. 

It  fends  another  Branch  of  coniiderable  fize  downwards  to  the 
Trunk  of  the  Third  Pair. 

It  fends  feveral  Branches  to  the  Sterno-maftoid  Mufcle,  behind 
which  it  is  connefled  by  an  Arch,  and  ffcill  farther  out  by  a Fila- 
ment, w th  the  Nervus  AccefTorius. 

It  is  afterwards  divided  into  feveral  Branches,  one  of  which 
partes  downwards  fome  way  upon  the  External  jugular  Vein, 
and,  toge'her  with  a Branch  from  the  Fil'd  Cervical,  forms  an 
Arch  with  the  Defcendens  of  the  Ninth  Pair. 

It  gives  off  a fmall  root  which  is  united  with  others  in  the  for- 
mation of  the  Diaphragmatic  Nerve. 

A Large  Branch  comes  out  from  it  behind  the  Sterno-Maftoi- 
deus,  which,  turning  over  this  Mufcle,  fends  off  the  following 
Nerves,  viz. 

"The.  Inferior  Cutaneous  Nerve  of  the  Neck,  which  partes  for- 
wards to  the  parts  under  the  Lower  Jaw  : 

The  Middle  Cutaneous  Nerve,  which  runs  towards  the  angle  of 
the  Jaw. 

The  Great  Poferior  Auricular  Nerve,  which  furnifhes  an  ante- 
rior Branch  to  the  under  part  of  the  Ear,  and  a pofterior  Branch 
div’ding  into  many  others  which  go  to  the  back-part  of  the  Ear 
and  Temple. 

The  Cutaneous  and  Auricular' Nerves  are  difperfed  upon  the 
Piatyfma  Myoides,  Integuments  of  the  fide  of  the  Neck  and 
Head,  the  Parotid  Gland,  and  External  Ear  and  have  leveral 
Communications  with  the  Poitio  Dura  of  the  Seventh  Pair. 


2-n 


The  remainder  of  the  Second  Cervical  is  diftributed  upon  the 
L'V’ior  Scapulas,  and  the  Extenlor  Mufcles  of  the  Neck  and 


Head 


The  Timo  Cervical  Nebve, — afier  emerging  from  be- 
tween the  Ve,  rebrae,  lends  down  a Branch  to  the  T.unk  of  the 
Fourth  Cervical,  a. id  another  Branch  which  forms  the  piincipal 
root  of  the  Diaphragmatic  Nerve. 

A 1 Third.  Branch  perforates  the  Mufcles  on  the  fide  of  t lie 
Vertebrae*  and  joins  the  middle  Ganglion  of  the  Sympathetic 
Nerve. 

A Small  Filament  conne&s  a Third  Cervical  with  the  De- 
feenden.-.  of  the  Ninth  Pair. 

The  Nerve  is  afterwards  divided  into  External  and  Internal 
Branches. 

The  External  Branches  form  Anaftomofes  with  the  Nervus 
Acceffonus,  near  the  upper  part  of  the  Scapula  ; wh  le  the  In- 
terior, after  furnifhing  Twigs  to  the  Jugular  Glands,  are  dif- 
perf’ed  by  feverai  large  Branches  upon  the  Mufcles  and  Integu- 
ments at  the  under  part  of  the  Neck,  and  upper  part  of  the 
Shoulder. 

The  Fourth  Cervical, — fends  a Branch  behind  the  Muf- 
cles (ituated  on  the  fore  and  lateral  parts  of  the  Cervical  Verte- 
brae, to  the  middle  Ganglion  of  the  Sympathetic  Nerve. 

It  is  connefted  by  one,  and  fometimes-  by  two  Filaments  to  the 
Diaphragmatic  Nerve. 

It  gives  Twigs  to  the  Jugular  Glands  and  deep  Mufcles  of 
the  Neck,  and  at  the  outer  edge  of  the  anterior  Scalenus,  joins 
the  Fifth  Cervical  Nerve. 

The  Fifth  Cervical, — is  united  with  the  Fourth  into  a 
Common  Trunk,  which,  after  running  a little  farther  out,  joins 
the  Sixth  Cervical  Nerve. 

The  Sixth  Cervical, — joins  the  Seventh  behind  the  Clavi- 
cle ; and  to  the  Seventh,  the  Firft  Dorfal  Nerve  is  added  over  the 
Firft  Rib. 


The  Four  Inferior  Cervicals  and  Firft  Dorfal  Nerve  are  of  great 
fize, — efpecially  the  three  intermediate  Nerves. 

They  pafs  out  between  the  Scalenus  Anticus  and  Medius,— ■ 
and  afterwards  run  between  the  Subclavian  Mufcle  and  Firft  Rib, 
at  the  ou  ef  fide  of  the  Subclavian  Artery,  to  the  Axilla. 

In  the  Axilla,  they  feparate,  unite,  and  fepurate  again,  form- 
ing an  irregular  Plexus,  termed  Axillary  or  Brachial , — which 
furrounds  the  Axillary  Artery. 

The  Axillary  Plexus  feuds  Branches  to  the  Subfeapularis,  Te- 
res Major,  and  Latiflimus  Doni,  and  furnifhes  the  External 
Thoracic  Nerves  which  accompany  the  Blood- vefiels  of  that 
name  to  the  Peftural  Mufcles  and  Integuments. 

The  Plexus  afterwaids  divides  into  Nerves,  moft  of  which  are 
of  great  fize,  to  fupply  the  Superior  Extremity. — They  are  as 
follow. 


The  Scapularis, — which  commonly  arifes  from  the  com- 
bination of  the  Fourth  and  Fifth  Pairs,  and  extending  outwards, 
runs  through  the  Semilunar  Arch  in  the  upper  edge  of  the  Sca- 
pula, afterwards  defending  between  the  root  of  the  Spine  and 
Head  of  the  Scapula. 

It  furnifttes  Blanches  to  the  Supra-Spinatus,  and  is  afterwards 
confumed  upon  the  Infra- Spinatus  Mulcle. 

The  Articulakis, — which  arifes,  like  the  former  Nerve, 
from  the  Trunk  common  to  the  Fourth  and  Fifth  Cervicals. 

It  finks  deep  in  the  Axilla,  and  getting  between  the  under 
edge  of  the  Subfcapularis,  and  Infertions  of  the  Teres  Major  and 
LatifTiinus  Dorfi,  it  follows  the  courfeof  the  Pofterior  Aiticular 
Artery  round  the  Body  of  the  Os  Humeri,  immediately  below 
the  Articulation. 

It  fends  Branches  to  the  Teres  M;nor,  and  fome  Twigs  to  the 
Ligament  of  the  Joint  ; but  is  chiefly  difperfed  upon  the  Deltoid 
Mulcle. 

The  Nervus  Cutaneus, — which  arifes  from  the  Trunk 
common  to  the  1 a It  Cervical  and  Fill  Doifal  Nerve  j but  is 
chiefly  formed  by  Fibrillae  from  the  latter. 

It  runs  down  at  the  inner  and  fore-part  of  the  Arm,  near  the 
Radial  Nerve. 

It  ibmetim.es  gives  a fmall  Branch  to  the  upper  part  of  the  Co- 
raco-brachialis  and  Biceps  ; and,  farther  down,  it  gives  others 
to  the  Integuments  and  Coats  of  the  Blood-velfels. 

About  the  middle  of  the  Aim,  it  fplits  into  two  Branches,  an 
Internal  and  External. 

Th a Internal  Branch,  which  is  rather  the  finaller  of  the  two, 
paffes  before  the  Balilic  Vein  to  the  inner  part  of  the  Elbow, 
■where  it  divides  into  Branches,  two  of  which,  larger  than  the 
reft,  turn  obliquely  over  the  Heads  of  the  Flexor^  of  the  Hand, 
to  be  difperfed  upon  the  inner  and  back-part  of  the  fore-arm. 

The  External  Branch  divides  into  feveral  others,  behind  the 
Median  Balilic  Vein,  which  delcend  on  the  anterior  and  Ulnar 
fide  of  the  Fore-arm,  as  far  as  the  Wrift. 

They  pafs  partly  over  and  partly  under  the  Subcutaneous 
Veffels  ; furnifhing  Twigs  to  thefe,  and  vanilliing  in  the  Integu- 
ments. 

Befides  the  Nervus  Cutaneus,  there  is  another  termed  Cutane- 
us Minor  of  Wrisberg,  which,  like  the  reft  of  the 

Nerves  of  the  Superior  Extremity,  takes  its  origin  from  the  Ax- 
illary Plexus  ; but  is  more  particularly  connected  with  the  Ul- 
nar Nerve. — It  is  confiderably  inferior  in  fize  to  the  Nervus  Cu- 
taneus. 

It  foon  feparates  from  the  Ulnar,  running  afterwards  between 
it  and  the  inner  fide  of  the  Arm. 

A little  below  the  Axilla,  it  fplits  into  two  Branches  : 


249 


The  fmaller,  turning  to  the  pofterior  part  of  the  Ann,  is  divi- 
ded into  Filaments  which  are  chiefly  difperled  upon  the  Triceps 
and  its  Integuments. 

The  larger  Branch  defcends  at  the  inner  edge  of  the  Triceps, 
and  vanilhes  upon  the  under  end  of  that  Mul'cle  and  Skin  of  the 
Elbow. 

The  Musculo-Cutaneus,  called  alfo  Perfcrans  Caserii, 
— which  coniifts  of  Fibrillse  from  almoft  all  the  Nerves  entering 
the  Plexus. 

The  Cord  formed  by  thefe  perforates,  obliquely,  the  upper 
part  of  the  Coraco-brachialis,  to  wh  ch  it  gives  Branches. 

It  afterwards  paffes  between  the  Biceps  and  Brachiahs  Inter- 
ims, furn idling  Branches  to  both. 

At  the  Elbow,  it  gets  to  the  outfide  of  the  Tendon  of  the  Bi- 
ceps, and  runs  behind  the  Median  Cephalic  Vein. 

From  thence  it  defcends  in  the  Fore-arm,  between  the  Supina- 
tor Longus  and  Integuments  ; furnifliing  Brandies  to  the  latter, 
as  far  as  the  root  of  the  Thumb  and  backof  ihe  Hand. 

The  Spiral,  or  Spiral-Muscular  Nerve, — which  is 
apparently  formed  by  all  the  Nerves  entering  into  ,he  Axillary 
Plexus,  and  when  the  Sheaths  of  the  Nerves  are  flit  open,  is  found 
to  be  compofed  of  Fibril'*  from  each  of  the  Trunks,  excepting 
from  that  of  the  Firft  Dorfal. 

It  is  rather  larger  than  any  other  Nerve  of  the  Superior  Ex- 
tremity, and  is  dillinguifhed  by  its  Spiral  direftion. 

It  is  at  firft  fituatec!  between  the  Axillary  Artery  and  the  Ul- 
nar Nerve,  and  palfes  obliquely  downwards  between  the  two 
Heads  of  the  Triceps  Extenfor  Cubiti,  and  afterwards  behind 
the  Os  Humeri,  to  the  outfide  of  the  Elbow. 

From  thence  it  p.oceeds  among  the  Mufcles  of  the  Radial  fide 
of  the  Fore-arm,  as  far  as  the  Hand. 

While  pafling  behind  the  Os  Humeri,  it  gives  feveral  Branch- 
es of  confiderable  fize  to  the  different  Heads  of  theTiiceps; 
fome  of  th.m  accompanying  the  Branches  of  the  Arteria  Spiralis, 
and  terminating  on  the  Heads  of  the  Extenfors  of  the  Hand. 

Immediately  behind  the  body  of  the  Os  Humeri,  it  tranfmits  a 
Subcutaneous  Branch,  which  is  d i Hi  i bu ted  upon  the  Mufcles 
and  Integuments  on  'he  pofterior  part  of  the  Fore-arm,  anaftomo- 
fing  at  laid  with  the  Nerves  on  the  back-part  of  the  Hand. 

The  Trunk  of  the  Nerve  having  arrived  at  the  Elbow,  is  lod- 
ged in  a F:  flu  re  between  the  Brachialis  Internus  and  Radial  Ex- 
tenfors  of  the  Carpus,  and  there  gives  off  other  Branches  to  the 
Extenfors  ot  the  Hand,  and  to  the  Supinator  Mufcles. 

At  the  Head  of  the  Radios,  the  Trunk  of  the  Nerve  divides 
in'o  two  nearly  equal  Branches, — the  Superficial!;  and  Profun- 
dus. 

The  Superficial!;,  continued  almoft  ftraight  from  the  Trunk, 
immediately  tranfmits  a Branch  to  the  Extcnfores  Radiales  and 


250 


Supinator  Longus,  and  then  defcends  at  the  inner  edge  of  this 
Mufcle  along  with  the  Radial  Artery. 

A little  below  the  middle  of  the  Radius,  it  erodes  between 
the  Tendon  i f the  Supinator  and  Extenlores  Radiales,  and  is 
fubdivided  into  a Volar  and  Dm  fal  Branch. 

The  Volar  Branch,  after  fending  Twigs  to  the  Annular  Li- 
gament, is  diftributed  to  the  Mufcles  and  Integuments  of  the 
Thumb. 

The  Dorfal  Branch  is  again  fubdivided  into  numerous  other 
Branches,  fome  of  which  go  to  the  Mufcles  in  the  inerval  of 
the  Metacarpal  Bones  of  the  Thumb  and  Fore-finger,  a few  Fi- 
laments being  diftributed  to  the  Annular  Ligament,  while  prin- 
cipal Branches  run  one  along  each  fide  of  the  Foie  and  Mid-fin- 
ger, and  hkewil'e  along  the  Radial  fide  of  the  Ring-finger. 

The  Ramus  Profundus,  after  fending  feveral  Branches  to  the 
Extenfores  Radiales  and  Supinator  Brevis,  perforates  the  latter, 
and  gets  to  the  back-part -of  the  Fore-arm. 

Alter  quitting  the  Supinator,  it  defcends  under  the  Extenfor 
Primi  Internodii  Pollicis  and  Extenfor  Digitorum  to  the  back  of 
the  Hand. 

In  tin's  courfe,  it  fends  Branches  to  the  different  Extenfors  of 
the  Thumb  and  Fingers,  and  at  length  degenerates  into  a (lender 
Branch,  which,  at  the  Wrift,  adheres  clofely  to  the  Annular 
Ligament,  where  it  has  a Ganglilortn  appearance,  and  is  difper- 
fed  partly  upon  this  Ligament  and  partly  upon  the  Membranes 
on  the  back  of  the  Metacarpus. 

The  Median  or  Radial  Nerve, — which  comes  from  the 
middle  and  lower  part  of  the  Plexus,  is  formed  by  Fafciculi  front 
all  the  Nerves  which  enter  the  Plexus,  and  is  nearly  of  a fimilar 
fize  with  the  Spiral  Newe. 

Ii  defcends  in  the  Arm  along  the  anter  or  furface  of  the  Hu- 
meral Artery,  to  which,  and  to  the  Deep  Veins,  it  adheres  firm- 
ly by  Cellular  Subftnnce. 

In  this  courfe,  it  does  not  give  off  any  confiderahle  Branches  ; 
— Twics,  however,  are  lent  from  it  to  the  Coats  of  the  Adjacent 
Veffels. 

At  the  bending  of  the  Elbow,  it  flips  over  the  Tendon  of  the 
Brachialis  Interims,  and  perforates  the  back-part  of  the  Pronator 
Teres  Mufcle. 

It  afterwards  pnfles  down  between  the  Flexor  Radialis  and 
Mufcuius  Subl’mis,  and  goes  in  the  middle  of  the  interval  of 
the  Radial  and  Ulnar  Artery  in  its  way  to  the  Hand. 

When  it  approaches  the  Fore  arm,  it  tranfmits  Blanches  to 
the  Pronator  Teres  and  Integuments  near  that  Mufcle. 

In  the  Flexure  of  the  Arm,  it  fumithes  Branches  to  the  Pro- 
nator, Flexor  Radialis,  and  Flexor  Sublimis,  and  an  Interotfe- 
ous  Branch  which,  in  fome  Subjefts,  receives  an  addition  from 
the  Spiral  Nerve. 


251 


The  Interojfecus  Nerve  gives  Branches  to  the  Flexor  Longus 
Pollicis,  and  ro  t .e  Flexor  Profundus  Digitorum,  defcends  upon 
th  interoffzous  L Lament  with  ihe  Veffels  of  that  name,  and  ter- 
minates in  the  Pronatoi  Qijadtaius. 

Near  the  Hand,  it  tends  a Branch  dividing  into  others,  which 
fup  !y  the  Mufcies  and  Integuments  forming  the  Ball  of  the 
Thumb. 

The  Trunk  of  the  Nerve  having  given  Branches  to  the  Fore- 
arm, patfes  under  the  Annular  Ligament  of  the  Wrilf,  where  it 
divides  into  Branches  which  are  fituatea  behind  the  Aponeuroiis 
Paimaris,  and  Superficial  Arch  of  the  Arteries. 

The  principal  Branches  in  the  Palm  come  off  in  three  divifions, 
from  which  feven  Nerves  of  confiderable  lize  are  dilfributed  to 
the  Thumb  and  Fingers.  Of  thefe,  two  go  to  the  Thumb,  and 
one  to  the  Radial  fide  of  the  Fore -finger  ; ihe  relt  c.  me  off  from 
two-forked  Trunks,  ne3r  the  Heads  of  the  Metacarpal  Bones, 
and  l’u  up  I y the  adjacent  fides  of  the  Fore  and  Middle,  and  of 
the  Middle  and  Ring-fin  er. 

Thefe  Blanches  lend  Twigs  through  the  Aponeuroiis  to  the 
Integument,  of  the  Palm,  and  others  to  the  Mufculi  Lumbri- 
cales  ; after  which  they  accompany  the  Arteries  fent  out  from  the 
Superficial  Palmar  Arch,  bellowing  Twigs  to  the  adjacent  parts 
of  the  Fingers,  at  the  points  of  which  they  terminate  by  nume- 
rous Fibres. 

The  Ulnar  Nerve, — which,  like  the  former,  is  of  great 
fize,  comes  off  chiefly  from  the  laft:  Cervical  and  Fil'd:  Dorfal 
Nerve. 

It  extends  along  the  infide  of  the  Triceps,  frequently  perfora- 
ting fome  of  its  Flelhy  Fibres,  and,  near  the  Elbow,  Hants  a lit- 
tle backwards,  to  get  into  a Groove  between  the  inner  Condyle 
of  the  Os  Humeri  and  Olecranon  of  the  Ulna.' 

From  thence  it  pafles  to  the  Fore-Arm,  where,  after  perfora- 
ting the  Heads  of  the  Flexor  Muicles,  it  joins  the  Ulnar  Artery 
a little  below  its  origin,  and  accompanies  that  veffel, — running 
behind  it  all  the  way  to  the  Hand'. 

Under  the  Axilla,  it  fometimes  receives  a Branch  from  the 
Spiral  Nerve;  and  from  this  connexion,  or  from  the  Trunk  of 
the  Ulnar  Nerve  itfeif,  a Subcutaneous  Branch  is  fent  off,  which 
runs  between  the  Triceps  and  Integuments,  furnifhing  Branches 
to  the  latter  for  a confiderable  way  along  the  Fore-arm. 

Near  the  under  end  of  the  Os  Humeri,  a Twig  or  two  com- 
monly go  to  the  inner  edge  of  the  Triceps. 

Under  the  bending  of  the  Elbow,  a Branch  is  given  out  to  be 
diftributed  upon  the  Belly  of  the  Flexor  Ulnaris. 

Immediately  below  the  former,  another  Branch  is  produced, 
which  is  difperfed  upon  the  Flexor  Profundus  Digitorum. 

About  the  middle  of  the  Fore-arm,  a Filament  is  tranfmitted 
which  adheres  to  the  Ulnar  Artery,  turniflting  fmall  Twigs  to 


-252 


the  Coats  and  Sheath  of  the  Artery,  and  terminating  in  the 
correfponding  p rts  of  the  Wi  ift,  and  Integuments  of  the  Palm. 

Near  the  end  of  the  Ulna,  a confiderable  Branch,  termed  Dor- 
fa/is,  is  lent  out,  which  turning  between  the  Flexor  Uinaris  and 
Urna,  is  directed  to  the  back  part  of  ihe  Hand. 

The  Dorfal  Nerve  fends  Branches  to  the  Integuments  of  the 
Weft  and  Metacarpus,  which  have  various  anaftumofes  with 
otheis  ot  the  Spiral  Nerve. 

It  lend- off  a Branch  which  proceeds  along  the  Ulnar  fide  of 
the  Little  Finger; — and  at  the  Heads  of  the  Metacarpal  Bones, 
another  fplitting  into  two  Branches  which  run  along  the  adjacent 
lides  of  the  Auricular. and  Ring-fingers. 

The  Trunk  of  the  Nerve  paffes  with  the  correfpond;ng  Artery 
over  the  Annular  Ligament  into  the  Palm,  where,  like  the  Ra- 
dial Nerve,  it  is  covered  with  the  Aponeurofis  Palmai  is. 

In  the  Palm,  it  divides  into  Superficial  and  Deep  Branches  ; 
the  former  deftined  chiefly  for  the  Fingers,  the  latter  for  the  deep 
region  of  the  Hand. 

The  Superficial  Palmar  Nerves  fiends— 

Branches  to  the  Ihort  Mul'cles  of  the  Little  Finger  : 

A Branch  to  the  Volar-ulnar  fide  of  the  Little  Finger  : and — 

Another,  which  is  loon  fiplit  into  two  fmaller  Branches  ; one  to 
the  Radial  fide  of  the  Little  Finger,  the  other  to  the  Ulnar  iide 
of  the  Ring-finger. 

The  Deep  Palmar  Nerve  links  in  between  the  Abdudlor  and 
Flexor  Parvus  Digiti  Minimi,  or  perforates  the  head  of  the  latter, 
and  forms  an  Arch  which  accompanies  the  Deep  Arch  of  the 
Arterie  , under  the  tendon  of  ihe  Flexors,  and  the  Lumbricales 
Mufcles. 

The  Deep  Nerve  gives — 

A Branch  to  the  Abdudlor  Minimi  Digity,  and  one  to  each  of 
the  Interoffei  : 

A Twig  to  each  of  the  Lumbricales,  which  enters  from  -be- 
hind. : 

Branches  to  the  Flexor  Brevis  and  Addtiftor  PollicL. 

The  Nerve  terminates  at  length  by  feveral  fhort  Branches 
upon  the  Abdudlor  Indicis  Mufcle. 

The  Nerves  on  the  Palm  and  correfiponding  parts  of  the  Fin- 
gers, like  the  Arteries,  are  much  larger  than  thole  of  the  oppo- 
lite  fide  of  the  Hand. 

The  Digital  Nerves  fiends  off  many  lateral  Branches  to  the  In- 
teguments and  other  parts  of  the  Fingers,  and  terminate,  each, 
by  a Brufh  of  Fibres,  at  the  Apices  of  the  Fingers. 

Between  the  Branches  of  the  Radial  and  Ulnar  Nerve,  differ- 
ent Anaftomofes  are  frequently  found  ; and  the  fame  may  be  ob- 
ferved.between  the  Nerves  of  the  Paimar  and  Dorfal  fide  of  the 
Fingers. 


25S 


Intzucosto-Humerales. — Befides  the  Nerves  of  the  Supe- 
rior Extremity  fent  fron  the  Brachial  Plexus,  there  are  others  be- 
longing to  it,  which  take  their  origin  from  the  Tntercolfal  Nerves, 
and  which  may  therefore  be  termed  Intercojio-Humerales . 

The  Intercofio-Humeral  Ner-ves, — confiftof  a Branch  from  the 
Second,  and  of  another  from  the  Third  Intercoftal  Nerves,  both, 
of  which  pafs  out  at  the  fore  and  lateral  parts  of  the  Thorax, 
the  one  under  the  Second,  and  the  other  under  the  Third  Rib. 

The  firft  Nerve  is  joined  by  a fmall  Branch  with  the  Cutaneous 
Nerve,  or  with  the  Cutaneous  biternus  of  Wrisberg,  and  is  af- 
terwards difperfed  by  numerous  Filaments  upon  the  Axillary 
Glands,  and  upon  the  Integuments  of  the  Axilla  and  of  the  in- 
ner part  of  the  Arm. 

The  Second  Nerve  is  conne&ed  by  one  or  more  Branches  with 
the  Firft,  and  fends  lome  Twigs  to  the  Axillary  Glands  ; but  is 
chiefly  diftributed  upon  the  Integuments  of  the  back-part  of  the 
Ann,  which  it  fupplies  with  many  Branches,  fbme  of  them  ex- 
tending as  far  as  the  Elbow. 


■oooooooo  ©oooooooo 


NERVES 

WITHIN 

THE  THORAX . 


THE  Nerves,  in  each  fide  of  the  Thorax,  confift  of  the 
Phrenic,  the  Pars  Paga  of  the  Eighth  Pair,  the  Great  Sympa- 
thetic, and  the  Intercojials  ; all  of  which  are  covered  and  conceal- 
ed by  the  Pleura,  till  they  are  expofed  by  difleftion. 

The  Phrenic  or  Diaphragmatic  Nerve,  has  a fmall 
Filament  from  the  Second  Cervical  ; but  is  chiefly  formed  by  a 
Branch  from  the  Third,  and  by  one,  and  fometimes  by  two, 
from  the  Fourth  Cervical  Nerve. 

It  defcends  in  the  Neck,  along  the  outer  and  fore-part  of  the 
Scalenus  Anticus  Mufcle,  and  enters  the  Thorax  behind  the  an- 
terior extremity  of  the  Firft  Rib,  between  the  Subclavian  Artery 
and  correfponding  Vein. 

VOL.  II. 


Y 


254 


In  the  Thorax  it  runs  clown  over  the  root  of  the  Lungs,  at  d 
then  paffes  along  the  Pericardium,  to  which  it  adheres  clofely  in 
its  way  to  the  Diaphragm. 

The  Right  Phrenic  has  nearly  a ftraight  direction  oppofite  to 
the  Superior  Cava  and  Right  Auricle  ; while  the  left  makes  a 
con  fid  (rafale  Curve  near  its  under  end,  correfponding  with  that 
part  of  the  Pericard  um  which  covers  the  point  of  the  Heart. 

Upon  the  Surface  of  the  Diaphragm,  the  Trunk  is  divided  in- 
to ieveral  Branches,  which  are  diftributed  in  a radiated  form  upon 
the  Flefhy  Tides  of  that  Mulcle. 

Pahs  Vaga. — The  Pars  Vaga,  upon  approaching  the  Thorax, 
fends  a Filament,  and  fumetimes  two,  termed  Cardiac  Nerves, 
which  join  the  Cardiac  Branch  of  the  Great  Sympathetic,  as  al- 
ready obfened. 

It  enters  the  Thorax  between  the  Subclavian  Vein  and  Artery, 
and  after  giving  off  the  Recurrent  Nerve,  paffes  behind  the  root 
of  the  Lungs. 

Recurrent  Nerve. — The  Recurrent, — is  reflected  up- 
wards, behind  the  Subclavian  Artery  in  the  right,  and  behind 
the  Arch  of  the  Aorta  in  the  left  fide  of  the  Thorax  ; in  confe- 
quenceof  which,  the  left  nerve  is  the  longer  of  the  two.  It  af- 
terwards afcettds  in  the  Neck,  adhering  to  the  pollerior  and  late- 
ral part  of  the  Trachea,  in  its  way  to  the  Larynx. 

It  is  connefted,  near  its  origin,  by  one  or  two  Branches  of  con- 
fiderable  fize,  with  the  adjacent  Ganglia  of  the  Great  Sympathe- 
tic Nerve,  and  from  the  oppolitefide  of  its  root,  fends  other  con- 
jiderable  Branches  to  join  thofe  of  the  Eighth  Pair,  in  the  for- 
mation of  the  Anterior  Pulmonary  Plexus  of  Nerves. 

Near  the  Subclavian  Artery,  it  is  connected  by  different  Fila- 
ments to  the  Superficial  and  deep  Cardiac  Branches  of  the  Sym- 
pathetic Nerve. 

In  its  afeent  in  the  Neck,  it  tranfmits  Pencils  of  Filaments, 
which  penetrate  the  Trachea,  and  are  dilperfed  upon  its  Internal 
Membrane. 

Behind  the  Thyroid  Gland,  it  fends  off  minute  Fibres  to  the 
beginning  of  the-Efophagus  and  bottom  of  the  Pharynx  and 
final  1 Twigs  to  the  Gland  itfelf. 

Upon  the  inner  fide  of  the  Thyroid  Cartilage,  it  furniflies  a 
Branch  which  continues  a remarkable  Anaftomofis  with  another 
from  the  Internal  Laryngeal  Nerve. 

At  the  back  part  of  the  Larynx,  it  is  divided  into  many  Fi- 
briliat,  which  are  diftributed  to  the  different  Mufcles  fixed  to  the 
Arytenoid  Cartilage  of  the  correfponding  fide. 

It  has  alfo  fome  connexions,  fmaller  than  the  one  already 
mentioned,  with  Branches  of  the  Internal  Laryngeal  Nerve,  and 
fends  minute  Fibril  Ice  to  the  Internal  Membrane  of  the  Larynx  ; 
from  which  circumftauce  the  Recurrent  Nerves  are  confidered  as 
the  principal  Inftruments  of  the  Organ  of  Voice. 


29, '> 

The  Pars  Vaga,  having  transmitted  the  recurrent  Nerve,  gives 
off  Filaments  which  form  connections  with  Brandies  anting  from 
tiie  urt  ot  ihc  Recurrent  of  the  fame  and  of  the  opposite  fide. 

They  anatfomofe  alfo  by  imall  Finn  !i  ■-  with  the  Cardiac 
Branch  of  the  Sympathetic,  and  then  pafs  to  the  fore-part  of  the 
Bronchi,  where  they  conilitu.e  what  is  termed  the  Anterior  Pul- 
monary Plexus  of  Nerves. 

The  /interior  Pulmona  y Plexus,  thus  formed  by  Branches  from 
the  Ei  . hth  Pair,  wi  h the  aflillance  of  other's  from  the  Recurrent 
and  Sy  : pathetic  Nerves, — exten  ts  acrofs  t .e  Great  Branches -of 
the  Pulmonary  Artery,  and  after  tranl'mitting  imall  Filaments  to 
the  Pericardium  and  to  the  Great  Cardiac  Nerve,  furni flies  many 
minute  Fibril.se,  which  accompany  the  R-atni ideations'  of  the 
Bronchi  and  Pulmonary  Blood-veffeis  in  the  l'ubfcunce  of  the 
Lungs. 

From  the  Pars  Vaga,  a little  below  the  origin  of  the  Recurrent, 
and  likewife  from  the  root  of  the  Recurrent  itfelf,  Nerves  are  feut 
ofF,  which  form  a Plexus,  to  be  difperfed  partly  upon  the  Flefhy- 
glandular  Suhifance  of  the  Trachea,  and  partly  embracing  the 
OEfophagus,  and  forming  upon  it  the  fniall  OEfophageal 
Plexus. 

Behind  the  root  of  the  Lungs,  about  fix  or  feven  Nerves  of 
different  fizes  are  fent  off  in  a tranfverfe  direction,  which  are 
termed  Pojier'tor.. Pulmonary  Plexus,  although  they  have  few  con- 
nexions with  each  other. 

The  Pofterior  Pulmonary  Nerves,  like  the  Anterior,  follow 
the  Branches  of  the  Bronchi  and  Blood-velfels  in  the  fob  ft  a nee  of 
the  Lungs,  and,  becoming  gradually  fmailer,  fend  erf  minute 
Twigs,  which  penetrate  the  A'r-Veffels,  and  are  ultimately  dif- 
perfed upon  their  Internal  Membrane. 

After  riving  out  the  Pulm unary  Nerves,  the  Pars  Vagaisfplit 
into  Cords  termed  Great  OEfophageal  Plexus,  which  l'urrounds 
the  OEfophagus,  lends  Filaments  into  its  Subdance,  and  is 
joined  by  Funiculi  of  the  Pais  Vaga  of  the  opposite  tide. — It  goes 
afterwards  through  the  Diaphragm,  to  be  distributed  upon  the 
Vifcera  of  the  Abdomen. 

From  the  Ganglia  of  the  Great  Sympathetic  Nerve,  at  the 
bo  tom  of  the  Neck  and  top  of  the  Thorax,  the  principal  Cardiac 
Nerves  are  produced,  which  are  difperled  upon  the  Heart ; while 
the  continuation  of  the  Trunk  of  the  Sympathetic  defeends  in  the 
Thorax  at  the  fide  of  the  Vertebrae. 

The  Cardiac  Nerves  of  the  Right  Side  conftft  of  the 
Cardiacus  Magnus  Profundus,  and  Cardiacus  Minor,  the  latter  of 
which  is  termed  by  Scarpa  Cardiacus  Aortee  > uperficialis . 

The  Cardiacus  Magnus  Profundus, — is  principally 
formed  by  Branches  from  the  Second  Cervical  Ganglion  of  the 
Sympathetic,  and  afterwards  receives  one  or  two  Filaments  from 


256 


the  Cardiacus  Supremus,  together  with  the  Superficial  Cardiac 
and  other  Branches  of  the  Eighth  Pair,  as  formerly  defcribed. 

The  Trunk,  arifing  in  this  manner  from  different  fources, 
partes  between  the  Superior  Cava  and  afcending  Aorta  to  the  Pof- 
teiior  Surface  of  the  latter,  and  joins  the  Cardiac  Branches  of 
theLeft  Side. 

By  the  addition  of  the  Left  Cardiac  Nerves,  a Plexus  is  formed, 
termed  Plexus  Cardiacus  Magnus  of  Haller,  from  which  is 
lent  out  a long  Ganglion  of  a loft  confidence,  defcribed  by 
W risberg  under  the  name  of  Ganglion  Cardiacum. 

From  The  Cardiac  Ganglion,  the  following  Branches  are  gi- 
ven off,  viz. 

A Branch  which,  after  tranfmitting  Filaments  to  the  Anterior 
Pulmonary  Plexus  of  the  Eighth  Pair,  partes  behind  the  Right 
Divifion  of  the  Pulmonary  Artery  to  the  Left  Coronary  Plexus 
of  the  Pleat  t .- 

One  or  two  Filaments,  which  unite  with  others  fent  from  the 
Anterior  Pulmonary  Plexus  of  the  Eighth  Pair,  and  go  before 
the  Right  Brandi  of  the  Pulmonary  Artery  to  the  Bafe  of  the 
Heart : 

Branches  of  confiderable  fize,  parting  partly  over  the  right  fide 
of  the  Aorta,  and  partly  between  it  and  the  Pulmonary  Artery 
to  the  Anterior  Coronary  Plexus  : 

Small  Branches  which  unite  with  others  coming  from  the 
Trunk  of  the  Great  Cardiac  Nerve,  and  pafs  over  the  Aorta  to 
the  Anterior  Coronary  Plexus. 

The  Nervus  Cardiacus  Minor  arifes  from  the  undermoft 
Cervical  Ganglion,  creeps  over  the  Arteria  Innominata  and  Aor- 
ta, and  terminates  in  a Plexus  formed  by  the  Cardiac  Nerves  on 
the  left  fide  of  the  Aorta  Afcendens. 

The  Left  Cardiac  Nerves  are,  the  Cardiacus  Superfci- 
alis,  and  the  Cardiacus  Magnus  Profundus. 

The  Cardiacus  Superfici alis  arifes  from  the  upper  part 
of  the  Sympathetic  Nerve,  as  formerly  noticed,  and  partes  be- 
hind the  Arch  of  the  Aorta  to  the  Plexus  Cardiacus  Magnus. 

The  Cardiacus  Magnus  Profundus  Sinister,  the  up 
per  portion  f which  is  fntaller  than  that  of  the  right  fide,  arifes 
by  numerous  roots  from  the  middle,  and  from  the  lowed  Gan- 
glion of  the  Sympathetic  Nerve. 

It  partes  aero fs  the  Arch  of  the  Aorta,  and,  after  receiving  the 
Cardiac  Branch  of  the  Eigluh  Pair,  joins  the  Great  Cardiac  of  the 
right  fide,  t . artful  in  forming  the  Cardiac  Plexus. 

From  the  Cardiac  Plexus,  a Reticulum  of  Nerves  extends  up- 
on the  left  fide  of  the  afcending  Aorta,  which  receives  the  Car- 
diacs Minor,  and  a Filament  or  two  from  the  Caidiacus  Mag- 
nus of  the  right  fide,  parting  over  the  Aorta. 

From  this  Reticulum,  the  Anterior  or  Right  Coronary  Plexus 
is  produced,  which  partes  between  the  Pulmonary  Artery  and 


257 


Aorta,  and  afterwards  follows  the  courfe  of  the  Trunk  and 
Branches  of  the  Right  Coronary  Artery,  along  with  which  it  is 
difperfed  upon  the  correfponding  fide  of  the  Heart. 

The  Great  Cardiac  Plexus,  after  fending  a Filament  or  two 
to  the  Lungs,  gives  off  Nerves  which  unite,  and  form  the  Trunk 
of  the  Great  Deep  Cardiac  Nerve  of  the  left  fide,  which  has  a foft 
Gangliform  appearance,  and  paffes  along  the  correfponding  iide 
of  the  Pulmonary  Artery. 

Upon  the  Surface  of  this  Artery,  the  Trunk  foon  divides  in- 
to Branches,  which,  after  fending  Filaments  acrofs  it  to  the  right 
Coronary  Plexus,  give  origin  to  the  Coronary  Plexus  of  the  left 
fide,  which  attends  the  Trunk  and  Branches  of  the  Left  Corona- 
ry Artery. 

In  the  Left  or  Pofterior  Coronary  Plexus,  the  Nerves  are  lar- 
ger than  in  the  Right,  correfponding  with  the  Parts  they  have 
tofupply;  and,  in  both,  they  have  repeated  connexions  with 
each  other  on  the  furface  of  the  Heart. 

In  general,  the  Nerves  run  cloie  to  the  Arteries  ; fome  of  them 
being  continued  as  far  as  the  Apex,  while  others  penetrate  the 
fubftance  of  the  Heart. 

The  Great  Sympathetic,  having  fent  Nerves  to  the  Heart,  con- 
lifts  of  an  anterior  and  pofterior  part, — the  former  going  over,  and 
the  latter  under  the  Subclavian  Artery. 

Behind  this  Artery,  the  two  parts  unite  into  a Trunk,  which 
defcends  in  the  Thorax  over  the  Heads  of  the  Ribs. 

At  the  Head  of  each  Rib,  it  fonns  a fmall  Ganglion  of  an  ir- 
regular lhape,  which  unites  behind  with  each  of  the  Intercoftal 
Nerves,  generally  by  two,  and  fornetimes  by  three  fliort  Bran- 
ches. 

From  feveral  of  the  Dorfal  Ganglia  of  this  Nerve,  Filaments 
are  detached  obliquely  over  the  Vertebras  to  the  Coats  of  the 
Aorta. 

From  the  Sixth,  Seventh,  and  Eighth  Dorfal  Ganglia,-— and 
frequently  from  a Ganglion  above  or  below  thefe, — Branches  a- 
life,  which  defcend  obliquely  upon  the  lides  of  the  Vertebrae, 
and  unite  into  a Trunk,  termed  Ner-vus  Splanchnicus,— which 
perforates  the  Appendix  of  the  Diaphragm,  and  goes  to  the  Vif- 
cera  of  the  Abdomen,  from  which  circumftance  the  Nerve  obtains 
its  name. 

Belides  the  Nervus  Splanchnicus,  another,  termed  Splanchni- 
cus Secundarius,  or  Accejj'orius,  is  generaliy  obferved,  which  a- 
rifes  from  one  or  two  of  the  Dorfal  Ganglia,  below  the  origins 
of  the  Splanchnicus, — near  its  termination,— -or  runs  feparate 
from  it  into  the  Abdomen. 

The  Intercostal,  or  Costal,  or  Dorsal  Nerves,— 
after  eicaping  from  th  Vertebrae,— run  in  the  Furrows  at  the 
lower  edges  of  the  Ribs,  in  company  with  the  Intercoftal  Blood- 

Vol.  II.  Y 2 


vefTeis,  and  proceed  to  the  anterior  part  of  the  Thorax,  between 
the  two  Layeis  of  Intercoftal  Mufcles. 

Immediately  after  getting  out  from  between  the  Vertebrae, 
each  is  connected,  as  already  noticed,  by  fhort  Branches  to  the 
Sympathetic  Nerve. 

Oppoiite  to  this  conne&ion,  they  give  principal  Branches, 
backwards,  to  the  Mufcles  lying  near  the  Spine,  and  ferving  for 
the  ereftion  of  the  Trunk  of  the  Body. 

Through  the  reft  of  their  courfe,  they  give  Branches  to  the  In- 
tercoftal  Mufcles,  to  the  Mufcles  and  Integuments  of  the  Tho- 
rax, and  alfo  to  tliofe  of  the  Abdomen,  and  becoming  gradually 
Smaller,  they  at  1 all  vanifh  in  the  fore-part  ©f  the  Body. 

The  Six  upper  Intercoftals  fends  Branches  to  the  numerous 
Mufcles,  and  to  the  Integuments  covering  the  back-part  of  the 
Thorax,  to  the  Serratus  Magnus,  and  to  the  upper  part  of  the 
Abdominal  Mulcles  ; while  the  remains  of  them,  parting  out 
between  the  Ribs  at  the  edge  of  the  Sternum,  are  reflected  along 
with  Branches  of  the  Internal  Mammary  Blood-vefiels,  to  be  dif- 
perfed  by  fmall  Filaments  upon  the  Mamma,  and  likewife  upon 
the  Mufcles  and  Integuments  next  the  edge  of  the  Sternum. 

The  Trunk  of  the  Fil'd  Intercoftal  enters  the  compofition  of 
the  Axillary  Plexus  ; — a Branch  of  it,  however,  runs  along  the 
edge  of  the  firft  Rib,  in  the  manner  the  other  Intercoftals  run  a- 
long  their  refpe&ive  Ribs. 

Two  principal  Branches,— one  from  the  Second,  and  the  other 
from  the  Third  Intercoftal,— are  occupied  in  forming  the  Inter- 
cofto-humeral  Nerves,  already  defcribed  5 while  a confklerable 
Branch  from  the  Fourth  is  reflected  over  the  edge  of  the  Latiffi- 
mus  Dorfi  to  the  Integuments  of  the  back-part  of  the  Thorax. 

The  Six  lower  Intercoftals,  after  fupplying  the  adjacent  Muf- 
cles and  Integuments  of  the  Thorax,  continue  their  courfe  ob- 
liquely forwards,  and  are  difperfed  upon  the  different  Mufcles 
and  Integuments  of  the  Abdomen  ; — the  Twelfth,  running  from 
the  laft  Rib  along  the  under  end  of  the  Abdomen,  fends  Fila- 
ments which  extend  as  far  as  the  Skin  of  the  Pelvis  and  Thigh. 


NERVES 


OF  THE 

CHYLOPOIETIC  AND  ASSISTANT  CHYLOPOIETIC 
VISCERA. 

THE  Nerves  of  the  Chylopoietic  and  Afliftant  Chylopoietic 
Vifcera,  are  formed  bv  Branches,  of  the  Par  Vagum,  and  the  Ra- 
mi Splanchnki  ot  the  Great  Sympathetic  Pair. 


259 


The  Pars  Vaga  of  the  Left  Side, — defcending  from  the  Great 
OEfophageal  Plexus  of  the  E'ghth  Pair,  creeps  along  the  fore- 
part of  the  Cardia,  detaches  Filaments  to  the  Left  Hepatic  Plex- 
us, and  divides  into  many  Branches  which  are  diftributed  to  the 
upper  and  left  portion  of  the  Stomach. 

The  Right  Pars  Vaga  paffes  upon  the  pofterior  part  of  the 
Cardia,  and  fplits  into  two  Fafciculi,  one  of  which  goes  to  the 
root  of  the  Hepatic  Plexus  and  to  the  Coeliac  Ganglion,  while 
the  other,  which  is  the  principal  one,  is  difperfed  by  numerous 
Branches  upon  the  under  and  left  portion  of  the  Stomach. 

The  Nerves  of  the  two  Falciculi  have  feveral  connexions  with 
each  other,  about  the  Cardia  and  along  the  fmall  Curvature  of 
the  Stomach,  and  form  a Plexus,  by  fome  Authors  termed  Coro- 
nary, from  which  Branches  extend  along  the  fmall  Curvature  as 
far  as  the  Pylorus. 

The  Ramus  Splanchnicus  and  Splanchnicus  Secun- 
DARIUS  have  their  origins  from  the  Sympatbetics,  and  perforate 
the  upper  and  lateral  part  of  the  inferior  Mufcle  of  the  Diaphragm, 
— as  already  mentioned  in  the  Defcription  of  the  Nerves  of  the 
Thorax. 

After  entering  the  Abdomen,  they  expand  their  Fibres,  and 
unite  with  the  lateral  part  of  the  Great  Semilunar  Ganglion. 

The  Semilunar  Ganglion, — is  formed  by  the  Rami 
Splanchnici  of  the  Right  and  Left  Sympathetics,  with  the  addi- 
tion of  the  Branches  from  the  Eighth  Pair. 

It  is  of  a long  curved  fhape,  with  the  convex  edge  nndermoff, 
and  is  compofed  of  many  fmaller  Ganglia,  termed  Coeliac,  which 
are  of  different  fize  and  of  irregular  forms. 

The  Coeliac  Ganglia  are  placed  over  the  Aorta,  about 
the  roots  of  the  Coeliac  and  Superior  Mefenteric  Arteries,  and 
extend  fome  way  upon  the  Flefhy  Pillars  of  the  Diaphragm. 

From  the  Coeliac  Ganglia  innumerable  Nerves  blue  on  all  lides 
forming  a Plexus,  termed  by  fome  Authors  Solar,  which  extends 
along  the  Trunks  and  Branches  of  the  Coeliac  and  Superior  Me- 
fenteric Arteries. 

The  Nerves  upon  thefe  Arteries  are  fo  intermixed  with  each  o- 
ther  and  with  Cellular  Subftance,  as  to  form  confufed  Webs  ; 
the  name  of  Plexus,  however,  is  (fill  retained,  and  the  particu- 
lar name  of  each  Plexus  is  derived  from  the  Artery  which  it  fur- 
rounds,  or  the  Vifcus  to  winch  it  belongs. 

The  Hepatic  Plexus, — after  giving  Twigs  to  the  Renal 
Glands,  fends  Filaments  to  the  Diaphragm,  which  accompany 
the  Diaphiagnmic  Arteries,  and  anafto.nofe  with  Branches  of 
the  Phrenic  Nerves. 

It  afterwards  du  :des  into  Ri^ht  and  L Plexufes,  correfpond- 
ing  with  the  Pigln  and  Left  B 'niches  of  the  Hepatic  Aitety,  or 
with  the  Right  and  Left  Trunks,  when  fuen  are  prefent. 


260 


The  Left  Hepatic  Plexus  furniflies  feveral  Branches  to  the  Sto- 
mach, which  intermix  with  thofe  of  the  Eighth  Pair,  upon  the 
fmall  Curvature. 

Th?  Right  Hepatic  Plexus  imparts  Branches  to  the  correfpond- 
ing  part  of  the  Pancreas,  to  the  fmall  end  of  the  Stomach  and 
beginn  ng  of  the  Duodenum,  and  gives  origin  to  the  Right  Gaf- 
tro- . p-ploic  Plexus,  which  attends  the  Artery  of  the  fame  name, 
diftnbuting  its  Filaments  to  the  great  Curvature  of  the  Stomach, 
and  to  tlu  Omentum  Majus. 

The  Hepatic  Plexufcs  lurround  the  Hepatic  Artery  and  Vena 
Portae,  and,  after  fending  feveral  Filaments  to  the  Biliary  Duffs 
and  Gall-Blarlder,  follow  the  Branches  of  the  Blood-veffels 
through  rhefubltance  of  the  Liver. 

The  Splen'c  Plexus,  coinpofed  of  feveral  fmall  Filaments, 
furrounds  the  Splenic  Artery,  gives  T igsto  the  Pancreas,  and 
then  accompanies  the  Veffels  into  the  Spleen. 

The  Superior.  Mesenteric  Plexus,  forms  a Vagina, 
which  furrounds,  and  in  a great  pa  t conceals  the  Trunk  of  the 
correfponding  Artery. 

From  this  Plexus,  numberlefs  Filaments  are  produced, — many 
of  them  extremely  minute, — which  run  through  the  Melentery, 
partly  with  the  Blood-veffels,  and  puily  atadillance  from  them; 
and  which,  after  fupplying  the  Coats  of  the  Veffels  and  Mefen- 
teric  Glands,  are  diftributed  to  the  fmall  Intellines  in  genera), 
and  to  the  right  portion  of  the  Colon. 

The  Nerves  of  the  Colon  are,  in  proportion  to  the  part  they 
have  to  ftipply,  larger  than  thole  of  the  Small  Inteftines,  and  in 
feveral  places  form  Arches,  wh.ch  are  fituated  at  the  fides  of  the 
Arteries. 

The  Coeliac  Ganglia  fend  down,  along  the  Aoria,  a Vagina 
fimilar  to  that  lurrounding  ihe  Superior  Mefenteric  Artery, 
which  is  joined  by  other  Nerves  from  the  Trunk  of  the  Sympa- 
thetic continued  along  the  Lumbar  Verteb:  as. 

From  the  Aortic  Vagina  or  Plexus,  a Ptocefs  is  fent  off,  term- 
ed Inferior  Mese  tery  Plexus,  which  furrounds  the 
Trunk  of  the  Inferior  Mefentei  ic  Artery,  and  follows  it  to  the 
left  portion  of  the  Colon,  and  to  the  Reftuin; — the  Nervous  Fi- 
laments forming  Arches  in  feveral  places,  as  in  the  Superior  Me- 
fenteric Plexus. 

The  Aortic  Plexus  receiving  frefh  fupplics  from  the  Trunks 
of  the  Sympathetic^,  fends  down  a Plexus,  commonly  termed 
Hypogc.fi’  ic,  which  pafles  ver  the  end  of  the  Aorta,  and, 
upon  the  laft  Lumbar  Vertebra,  fplits  into  right  and  left  por- 
tions, which  defcend  to  the  Vifcera  contained  in  the  Pelvis. 


261 


NERVES 

OF  THE 

ORGANS  OF  URINE  AND  GENERATION. 

THE  Nerves  of  the  Organs  of  Urine  and  Generation  conlift 
of  the  Renal  and  Hypogajlric  Plexus,  and  of  the  Spermatic  and 
Pudic  Branches. 

The  Renal  Plexus  is  compofed  of  Nerves  fent  from  the 
Coeliac  Ganglia,  joined  by  fome others  derived  from  one  or  two 
of  the  Ganglia,  of  the  Sympathetic  Nerve  in  the  bottom  of  the 
Thorax. 

It  is  interfperfed,  at  its  beginning,  with  fmall  Ganglia,  termed 
Renal,  and  is  afterwards  divided  into  Anterior  and  Pofterior 
Plexufes,  which  extend  along  the  correlponding  Surfaces  of  the 
Renal  Artery  to  the  Subftance  of  the  Kidney. 

From  the  Renal  Plexus,  fmall  nervous  Twigs  afcend  to  the 
Renal  Gland,  which  is  turnilhed  with  others  from  the  Coeliac 
Ganglia  and  root  of  the  Hepatic  Plexus. 

The  Renal  Plexus  alfo  fends  down  Filaments  to  fupply  the’up- 
per  portion  of  the  Ureter  ; — the  under  receiving  Nerves  from 
the  Hypogaftric  Plexus. 

The  Hypogastric  Plexus,  the  origin  and  courfe  of  which 
have  been  already  mentioned,  is  connefled  by  different  Nerves  to 
the  adjacent  Trunks  of  the  Great  Sympathetic  and  Sacral  Nerves, 
and  fends  many  Filaments  to  the  Reftuni,  Bladder,  and  Sper- 
matic Veffels  in  the  Male  ; and  to  the  Reftum  Bladder,  Uterus, 
and  Vagina  in  the  Female. — The  Nerves  of  the  Uterus  are  pro- 
portionally fmall.  They  pafs  into  its  fubftance  at  the  Cervix, 
and  follow  the  courfe  of  the  Blood-vefTels. 

Spermatic  Nerves. — The  Spermatic  Nerves  are  very  mi- 
nute— They  confift  of  a Superior  or  Internal,  anti  of  an  Inferi- 
or or  External  fet  of  Capillary  Branches. 

The  former  are  derived  from  the  Renal  and  Aortic  Plexus, 
and  accompany  the  Spermatic  Blood  veffels  in  their  courfe 
through  the  Abdomen,  and  afterwards  to  the  TefHcle. 

The  latter  are  fent  off  from  a Branch  of  the  Second  Lumbar 
Nerve,  which  running  behind  the  Tendon  of  the  External  Ob- 
lique Mulcle,  near  Poupart’s  Ligasnent,  detaches  a Filament, 
whichf  in  the  Male,  goes  to  the  Spermatic  Cord,  and  more  par- 
ticularly to  the  Cremafter  Mulcle;  and  in  the  Fem-.le,  is  reflec- 
ted along  the  L'gamentum  Rotundum  to  the  Uterus. 

Nervi  Pudici. — The  Nervi  Pudici  arife  in  two  Fafciculi, — a 
Superior  and  Inferior — which  are  formed  by  Fibrillae  from  all  the 
Cords  entering  the  compoution  of  the  Sciatic  Nerve. 


262 


The  Superior  Fafciculus  is  formed,  more  particularly,  by 
Threads  fi  -om  the  two  under  Lumbar  and  two  uprer  Sacral 
Nerves  the  Inferior  is  compofed  of  a fmall  Cord  from  the  Se- 
cond, and  a large  one  from  the  Third  Sacral. 

The  Fafcicub  pafs  through  the  under  part  of  the  Notch  of  the 
Os  Ilium,  and  afterwards  between  the  Sacro  feint ic  Lit  aments, 
ami  follow  the  Pudic  Blood-vefitls,  anallomofing  in  f 6 me  places 
with  each  other  by  Oblique  Branch  s. 

They  fend  many  Blanches  to  the  Mufcles  and  other  parts  about 
the  Anus  and  Perineum,  and  then  pafs  forwards  to  fupply  the 
different  parts  of  the  Penis. 

On  the  Penis,  the  Nerves  follow  the  courfe  of  the  Arteries,  the 
Superior  Fafciculus  conllituting  the  Nervus  Dorfali  , and  the  In- 
feri  or  iving  Blanches  to  the  under  part  of  tiie  Penis. 

The  Nervus  Dorfalis  which  is  the  mod  conhderable  of  th.e 
Penis,  runs  forwards  between  the  correfpdnding  Aitery  and  Vena 
Magna,  expanding  into  many  Branches  which  after  fupplying 
the  Corpus  Cavernofum  and  Teguments  of  the  correlponding 
fide,  terminate  in  the  Subltanceof  the  Glands. 


NERVES 


OF  THE 

LOINS,  PELVIS,  AND  INFERIOR  EXTREMITY. 

THE  Nerves  of  the  Loins,  Pelv’sy  and  Inferior  Extremity, 
con  lift  of  the  continuation  or  inferior  portion  of  the  Sympathetic, 
and  of  the  Trunks  and  Branches  of  the  Lumba  and  Sacral 
Nerves. 

The  Sympathetic  Nerve,  after  reaching  the  Abdomen, 
makes  a fweep  forw  ixls  upon  the  anterior  and  lateral  part  of  the 
Lumbar  Vertebrae,  between  the  Tendinous  Crura  of  the  Dia- 
phragm and  the  Pfoas  Mufcle. 

It  afterwards  defeends  into  the  Pelvis,  nearly  of  the  fame  fize 
as  in  the  fuperior  paits  of  the  Body,  and  pailes  over  the  anterior 
Surf.ce  of  the  Os  Sacrum,  at  the  inner  fide  of  the  Great  Sacral 
Foramina. 

Towards  the  lower  part  of  the  Pelvis,  it  becomes  conftderably 
fmaller,  and  at  laft  finifltes  its  courfe  upon  the  furface  of  the  Os 
Coccygis,  where  it  unites  into  an  Arch  with  its  fellow  of  the  op- 
pofite  fide. 


In  the  Loins,  it  forms  Ganglia  fimilarto  thofe  in  the  Thorax, 
each  of  which  is  conne&ed  behind,  by  two  or  three  long  (lender 
Branches,  to  the  roots  of  the  Lumbar  Nerves,  and  before,  by 
other  (lender  Nerves  to  the  Aortic  Plexus. 

In  the  Pelvis  alfo,  it  forms  Ganglia  which  are  connected  to  the 
Sacral  Nerves  on  one  fide,  and  to  the  Great  Sympathetic  on  the 
other,  by  crofs  Branches. 

Filaments  are  fent  off  in  the  Pelvis,  from  the  Sympathetic  to 
the  Mufcles  and  Membranes  about  the  Os  Coccygis,  and  to  the 
Inteftinum  Reftum. 

Lumbar.  Nerves. 

The  Five  Lumbar  Nerves,  immediately  after  emerging 
from  theBones,  communicate  with  each  other  and  with  the  Sym- 
pathetic Nerve,-  and  lend  large  Blanches  backwards  to  the  Muf- 
cles and  Integuments  on' the  pofterior  part  of  the  Loins. 

By  the  r connections  with  each  other,  they  compofe  a Piexus 
termed  Lumbar,  which  is  iiruated  behind  the  Pfoas  Mufcie,  and 
fends  Branches  outwards  to  the  Quadratus  Lumborum,  and  to 
the  Flexors  of  the  Thigh. 

The  First  .Lumbar  Nerve  is  connected  by  a final!  Branch 
to  the  Twelfth  Dorfal,  and  by  its  Trunk  to  the  Second  Lum- 
bar. 

It  gives  Twigs  to  the  Quadratus,  and  a principal  Branch  which 
pafles  over  that  Mulcle  towards  the  Spine  of  the  Os  ll  um, 
where  it  fends  Nerves  to  the  Integuments  of  the  Pelvis  to  the  up- 
per and  outer  pait  of  the  Thigh,  to  the  un.ier  end  of  the  Abdo- 
minal Mufcles,  and  to  the  Integuments  of  the  Pubes. 

The  Second  Lumbar  perforates  the  Pfoas,  to  which  it  gives 
Branches}  and  afterwards  runs  into  the  Third. 

From  tne  Second  Lumbar,  the  Spermaticus.Jixternus  is'  fent 
off,  which  perforates  the  under  part  of  the  Tranfverfe  and  Inter- 
nal Oblique  Muicies,  near  the  anterior  encTof  the  Spine,  or  Creft 
of  the  Ilium. 

It  goes  next  under  the  Tendon  of  the  External  Oblique,  at 
the  inner  fide  of  Poup  art’s  Ligament,  and  palling  through  the 
Abdominal  Ring,  is  dilfributed  to  the  Scrotum  and  to  the  Sper- 
matic Cord  in  the  Male. 

In  the  FemaL,  it  lends  a Branch  to  the  Labia,  and  another, 
reflected  along  the  Ligamentum  Rotundum,  to  the  Uterus  ; and 
in  both  Sexes,  it  gives  Branches  alfo  to  the  Integuments  and 
Glands  of  the  Groin. 

Another  Branch,  fmaller  than  the  former,  arifes  alio  from  the 
Second  Lumbar,  and  palling  between  the  Pfoas  Mufcie  and  Ver- 
tebrae, conftitutes  the  Cutanec  u;  Med'us  of  the  Thigh. 

The  Cutaneous  Medius  defeends  in  the  fore  part  of  the  Thi<di, 
oppolite  to  the  inner  edge  of  the  Rt&us  Mufcie,  and  fupplies  the 
Integuments  near  it  as  far  as  the  Knee, — one  Branch  of  it  anaf- 
tomofmg  with  another  of  the  Cutaneus  Anterior. 


Branches  of  the  Second,  Third,  and  Fourth  Lumbars,  form 
a Nerve  of  confiderabie  fize,  called  Obturator , which  palfes  be- 
tween the  External  and  Internal  Iliac  Blood-vefl'els,  and  along  the 
fide  of  the  Pelvis. 

The  Ob  turator  Nerve  accompanies  the  Blood-velfels,  of 
the  fame  name,  through  the  upper  part  of  the  Obturator  Muf- 
cles  and  Ligament,  and  having  furnifhed  Branches  to  the  Ob- 
tutator  and  Pedlineus  Mtifcles,  it  divides  into  an  Anterior  and 
Pofterior  Fafculus  ; the  former  difperfed  upon  the  two  fmall 
Addudtors  and  Gracilis,  the  latter  upon  the  Great  Adduftor  of 
the  Thigh. 

The  principal  parts  of  the  Trunks  of  the  four  upper  Lumbar 
Nerves,  efpecially  of  the  Third  and  Fourth,  unite  and  form 
a Nerve  of  great  fize,  termed  Crural , or  Anterior  Crural. 

The  Crural  Nerve,  after  bellowing  Branches  upon  the 
Iliacus  Interims,  pafl'es  behind,  then  at  the  outtide  of  the  Pfoas 
Mufcie,  to  get  to  the  Thigh. 

In  its  courfe  from  the  Abdomen,  and  at  the  upper  part  of  the 
Thigh,  it  is  fituated  at  the  outfide  of  the  Femoral  Artery,  which 
lies  between  it  and  the  correl'ponding  Vein. 

Behind  Poupart’s  Ligament,  it  is  divided  into  many  Branch- 
es, which  are  dilfributed  to  the  Mufcles  and  Integuments  on  the 
fore  and  lateral  parts  of  the  Thigh,— one  Branch  in  particular  de- 
fending upon  the  Leg. 

The  Branches  are  as  follow  : 

The  Cutaneus  Anterior, — more  internal  than  the  Cutaneous 
Ivied i us,  which  erodes  over  the  middle  of  the  Sartorius  Mufcie, 
and  after  fupplying  the  adjacent  Integuments,  terminates  in  the 
Skin  and  Cellular  Subftance,  at  the  fore  and  inner  part  of  the 
Knee. 

The  Cutaneus  Internus , — (fill  more  internal  than  the  former, 
—which  paffes  between  the  Sartorius  and  Triceps,  and,  after 
giving  Filaments  to  the  Integuments  at  the  iniide  of  the  Thigh, 
terminates  in  thofe  at  i he  under  and  fore  part  of  the  Knee. 

The  Deep  Branches  of  the  Crural  Nerve,  which  are  confide- 
rably  larger  than  the  Superficial,  go  to  the  Pedlineus  and  Tri- 
ceps, to  the  Sartorius  and  Gracilis,  and  to  the  four  Extenfors 
of  the  Leg,  and  furnifh  Twigs  to  the  Femoral  Blood-velfels 
alfo. 

The  Branch  to  the  Leg,  termed  Saphenus,  defends  between 
the  Sartorius  and  Triceps,  and  afterwards  behind  the  Tendon  of 
the  former,  to  the  inner  fide  of  the  Tibia. 

Under  the  Knee,  it  gives  off  a Branch,  named  by  Fischer, 
Saphenus  Minor,  which  goes  down  a little  behind  the  Saphenus, 
and,  furnifhing  Filaments  to  the  Integuments  of  the  inner  and 
back-part  of  the  Leg,  terminates  behind  the  Malleolus  Internus, 
on  the  Integuments  of  the  Foot. 


265 


The  Trunk  of  the  Saphenus  attends  the  Vena  Saphena  Major,, 
fending  many  Nervous  Threads  obliquely  forwards  to  the  Inte- 
guments on  the  inner  and  fore-part  of  the  Leg,  and  is  at  length, 
confumed  upon  the  Skin  and  Cellular  Subftance  of  the  upper  and 
inner  part  of  the  Foot. 

The  remaining  part  of  the  Fourth  Lumbar  Nerve  unites  with 
the  Fifth  into  a Trunk  which  defcends  into  the  Pelvis. 

Sacral  Nerves. 

The  Sacral  Nerves  confift  of  fmall  Poferior,  and  large 
Anterior  Trunks. 

The  Posterior  Sacral  Nerves  pafs  out  by  the  Holes  in 
the  back-part  of  the  Os  Sacrum,  and  anaftumofe  with  each  other, 
and  with  fome  of  the  Branches  of  the  Gluteal  Nerves. 

They  fend  out  a few  tender  Fibrillas,  which  are  difperfed  upon 
the  Mufcles  covering  the  back-part  of  the  Os  Sacrum,  and  upon 
the  Glutei  Mufcles  and  their  Integuments. 

Anterior  Sacral  Nerves. — Of  the  Anterior  Sacrals,— 
the  two  uppermoft  are  the  larged::  The  red:  1'uddenly  dimimlh  in 
fize,  the  lad  being  the  fmalleft  of  the  Spinal  Nerves. 

They  go  through  the  Holes  in  the  fore-part  of  the  Os  Sacrum, 
and,  foon  after  their  exit,  are  united  with  each  other,  and  with 
Branches  of  the  Sympathetic  Nerve. 

The  First,  Second,  and  Third  Sacrals,  join  into  a 
Trunk,  which  receives  the  common  one  fent  down  from  the  Fourth 
and  Fifth  Lumbars,  and  forms  a Plexus  which  fends  out  the  Scr- 
atic,  the  larged:  Nerve  of  the  Body. 

The  roots  of  the  Sciatic  Nerve  give  origin  to  the  Fafciculi 
which  compofe  the  Pudic  Nerve,  formerly  defcribed,  and  alfo  to 
the  Gluteal  Nerves  which  are  difperfed  upon  the  Mufcles  of  the 
Hips. 

The  Gluteal  Nerves  run  in  two  Fafciculi,— a Superior, 
arifing  immediately  from  the  Trunk  formed  by  the  two  lad  Lum- 
bars, and — an  Inferior,  coming  off  from  the  two  lad  Lumbars 
and  fird  Sacrals. 

The  Superior  Fafciculus  goes  through  the  upper  part  of  the 
Notch  of  the  Os  Ilium,  to  be  difperfed  upon  the  two  fmaller 
Glutei  Mufcles. 

The  Inferior  Fafciculus  paffes  through  the  under  part  of  the 
fame  Notch,  and  below  the  Pyriform  Mufcle,  to  be  didxibuted 
upon  the  Gluteus  Maximus  and  Integuments. 

The  Fourth  Sacral  fends  Filaments  to  the  Hypogadric 
Plexus,  others  to  the  Mufcles  and  Ligaments  of  the  Os  Coccy- 
gis ; the  red  pafs  outwards  to  the  Mufcles  and  Integuments  about 
the  Anus. 

The  Fifth,  which  is  fcarcely  above  the  fize  of  a Filament, 
after  giving  Twigs  to  the  Coccygeus  Mufcle,  perforates  the  Sa- 

Vol.  II.  Z 


266 


•cro-fciatic  Ligaments,  and  terminates  in  the  Mufcles  and  Integu- 
ments of  the  Anus. 

Sciatic  Nerve. — The  Sciatic  or  Ifchiatic  Nerve, — paffes  ob- 
liquely through  the  Notch  of  the  Ilium,  under  the  Pyriform  Muf- 
cle.  It  goes  afterwards  over  the  other  (hort  Rotator  Mufcles, 
and  is  placed  between  the  Tuber  Ifchii  and  Trochanter  Major, 
•where  it  is  coveied  by  the  Gluteus  Maximus. 

After  leaving  the  Pelvis,  it  defcer.ds  in  the  back-part  of  the 
Thigh,  firft  between  the  Long  Flexors  and  Addudlor  Magnus, 
and  then  between  the  latter  and  Os  Femoris  to  the  Ham,  where 
it  obtains  the  name  of  Popliteus. 

In  this  courfe,  it  gives  out  the  following  Branches,  which  fup- 
p'ly  the  Mufcles  and  Integuments  on  the  back-part  of  the  Thigh, 
viz. 

T<ivigs  to  the  Rotators  of  the  Thigh,  which  come  off  from  it 
after  its  palfage  through  the  Sciatic  Notch. 

The  Cutaneous  Pojlerior  Superior,  which  arifes  wifhin  the  Pel- 
vis, and  palling  out  with  the  Sciatic,  is  divided  into  Branches, 
fome  of  which  are  refle&ed  to  the  Scrotum  in  the  Male,  and  to 
the  polterior  parts  of  the  Labia  in  the  Female,  and,  in  both,  to 
the  Skin  aboat  the  Anus  and  Peiineum. — The  principal  Branches 
of  this  Nerve  pafs  downwards,  fupplying  the  Integuments  of  the 
back -part  of  the  Thigh,  as  far  as  the  bending  of  the  Knee. 

A Branch  to  the  long  Head  of  the  Biceps. 

Two  fmall  Nerves,  the  one  termed  Cutaneus  Internus  Superior , 
which  comes  off  near  the  upper  part  of  the  Thigh,  and  vanifhes 
in  the  Skin,  a little  farther  down  ; the  other  termed  Cutaneus  In- 
ternus Inferior,  which  arifes  near  the  former,  goes  down  the  pof- 
terior  part  of  the  Thigh,  and  then  defeending  upon  the  inner 
Head  of  the  Gallrocnemius  Externus,  terminates  in  the  Integu- 
ments of  the  Calf  of  the  Leg. 

A Large  Common  Trunk,  and  fometimes,  inftead  of  it,  fepa- 
ratc  Branches,  which  arife  near  the  middle  of  the  Thigh,  and 
are  diilri buted  to  the  Adduflor  Magnus,  Semimembranolus,  Bi- 
ceps, and  Semitendinofus. 

Nervus  Popliteus. — The  Popliteal  Nerve  is  fituated  be- 
tween the  Ham-ftrings,  and  between  the  Skin  and  Popliteal 
Blood-veffels. 

A little  above  the  bending  of  the  Knee,  it  is  divided  into  a 
Small  External,  and  a Large  Internal  Branch  ; the  former  named 
Fibular,  and  the  latter  Tibial  Nerve. 

The  Tibial  and  Fibular  Nerves  adhere,  for  fome  way,  by  Cel- 
lular Subftauce,  and  even  the  Trunk  of  the  Sciatic  may  be  fplit 
into  thefe  two  Nerves  for  a confiderable  way  up  the  Thigh. 

The  Fibular, — tefmed  alfo  Peroneal  Nerve, — fends  off, 
at  its  beginning,  the  Cutaneus  Externus,  which  is  a fmall 
Branch  giving  Twigs  to  the  under  end  of  the  Biceps,  and  which, 


267 


after  running  down  on  the  Outer  Head  of  the  Gaftrocnemius, 
difappears  in  the  Integnmenis  of  the  fame  fide  of  the  Leg. 

Over  the  outer  Condyle  of  the  Os  Femuris,  it  gives  off  another 
Cutaneous  Branch,  winch  goes  over  the  Gaftrocnemius  Mufcle, 
and,  after  anaftomofing  with  a Branch  of  the  Tibialis,  goes  along 
the  outer  part  of  the  Leg,  and  terminates  in  the  Integuments  of 
fide  of  the  foot. 

The  Fibular  Nerve  afterwards  paffes  over  the  Head  of  the  Fi- 
bula, and  divides  into  Superficial  and  Deep  Branches , which  fup- 
ply  the  Mufcles  and  Integuments  of  the  outer  and  fore-part  of 
the  Leg. 

The  Superficial  Fibular  croffes  over  the  Fibula,  immediately 
under  its  articulation,  and  perfoiating  the  Peroneus  Longus,  and 
going  over  the  Brevis,  it  gives  Branches  to  both,  and  after- 
wards becomes  Subcutaneous,  about  the  middle  of  the  outerparts 
of  the  Leg. 

It  fends  Branches  to  the  Metatarfus,  to  the  Extenfor  Digitorum 
Brevis,  and  others,  which,  after  anaftomofing  upon  the  upper 
part  of  the  Foot,  fumilh  Dorfal  Branches  to  the  larger  Toes. 

The  Deep  Fibular  Nerve  croffes  over  the  Fibula  immediately 
above  the  former,  and  divides  into  feveral  Branches,  viz. 

A Reflected  Branch  tG  the  foft  parts  of  the  joint  t 

A Branch  to  the  Peroneus  Longus  r 

A Branch  to  the  Tibialis  Anticus  ; 

Branches  to  the  Extenfor  Pollicis.  and  Extenfor  Digitorum 
Longus  : 

Filaments  which  creep  along  the  Perioftcum  of  the  Tibia,  and 
others  which  adhere  to  the  Coats  of  the  Tibia!  Artery. 

The  longeft  Branch  of  the  Nerve  accompanies  the  Anterior 
Tibiai  Artery,  and  divides  upon  the  Foot  into  Branches,  which-  - " 
have  fome  connexions  with  each  other,  and  fupply  the  Exten- 
for Digitorum  Brevis.— Some  Filaments  continued  from  thefe 
Branches  run  to  the  Mufculi  Interoffei,  while  others  of  more 
confiderable  fize  go  to  l’ome  of  the  innermoft  Toes,  one  Twig 
finking  with  a Branch  of  the  Anterior  Tibiai  Artery  to  the  Deep 
Mufcles  of  the  Sole. 

The  Tibial  Nerve  paffes  between  the  Heads  of  the  Gaftroc- 
nemius Mufcle,  and,  after  perforating  the  origin  ©f  the  Soleus, 
defeends  between  it  and  the  Flexor  Digitorum  Longus,  upon  he 
Pofterior  Tibiai  Artery,  to  the  under  part  of  the  Leg  j in  which 
courfe  it  fends  off  the  following  Nerves,  viz. 

The  Communicans  Tibia, — -which  accompanies  the  Vena  Saphe- 
na Minor  in  the  back  part  of  the  Leg,  and  to  the  outer  part  of 
the  Foot- 

Behind  the  Belly  of  the  Gaftrocnemius,  the  Communicans 
fends  a Branch  to  be  confumed  in  the  Fat ; and  a little  lower,  it 
anaftomofes  with  the  communicating  Branch  of  the  Fibular 
Nerve. 


268 


The  under  part  of  this  Nerve  is  difperfed  upon  the  Integuments 
of  the  outer  Ankle  and  adjacent  fide  of  the  Foot,  fome  Branches 
pafling  as  far  as  the  Dorfal  fide  of  two  or  three  of  the  fmaller 
Toes. 

Branches  to  both  Heads  of  the  Gaftrocnemius,  to  the  Planta- 
ris,  and  to  the  Soleus. 

Near  the  middle  of  the  Leg,  it  fends  Branches  to  the  Tibialis 
Pofticus,  to  the  Flexor  Digitorum  and  Flexor  Pollicis. 

One  or  two  Cutaneous  Branches,  difperfed  upon  the  Skin  at  the 
under  and  inner  part  of  the  Leg. 

Near  the  Ankle  a Branch  which  pafl'es  behind  the  Tendo  Achil- 
lis,  principally  to  the  Integuments  of  the  outer  and  back-part  of 
the  Foot. 

Tlie  Tibial  Nerve  pafl'es  afterwards  between  the  Arteries  and 
Os  Calcis  into  the  Sole. 

In  the  hollow  of  the  Os  Calcis,  after  detaching  Branches  to 
the  parrs  adjacent,  it  divides  into  Internal  and  External  Plantar 
Nerves,  which  are  nearly  of  equal  fize. 

. The  Internal  Plantar  Nerve  runs  near  the  inner  fide  of 
the  Sole,  fends  Filaments  to  the  Abduftor  Pollicis,  Flexor  Digi- 
torum Brevis,  and  Flexor  Digitorum  Acceflorius,  and  Twigs  to 
the  Lumbricales. 

It  afterwards  gives  out  four  large  Branches  fplitting  into  others, 
which  run  with  the  Arteries  along  the  Plantar  fides  of  the  three 
firft  Toes,  and  inner  fide  of  the  fourth  Toe, — in  the  manner  the 
Radial  Nerve  runs  along  the  correfponding  Fingers. 

The  External  Plantar  Nerve,  fends  branches  to  the 
Heel,  and  pafl'es  with  the  Artery  of  the  fame  name  to  near  the 
outer  edge  of  the  Sole,  where  it  fpl its  into  three  principal  Bran- 
ches. 

The  two  firft  run  to  the  adjacent  fides  of  the  fourth  and  fifth 
Toes,  and  outer  fide  of  the  Little  Toe,  the  inner  one  often  an- 
aflomofing  with  a correfponding  Branch  of  the  Internal  Plantar. 

The  thiid  forms  an  Arch  correfponding  with  that  of  the  Ex- 
ternal Plantar  Artery,  furnifhes  Bran-  hes  to  the  fliort  Mufcles 
of  the  Little  Toe,  to  the  Interoflei,  Lumbricales,  and  Tranfver- 
falis,  and  terminates  in  the  fhort  Mufcles  of  the  Great  Toe. 

The  Plantar  Digital  Nerves  fend  Filaments  to  the  Integu- 
ments, and  upon  the  Toes  anaftomofe  with  each  other,  and  with 
the  Dorfal-digital  Nerves, — as  the  Palmar  Digital  Nerves  do  in 
the  Hand. 


FINIS. 


INDEX  TO  FYFE’S  ANATOMY. 

VOLUME  SECOND. 


A 


Page. 

Page. 

Abdomen,  Of  the 

91 

Appendices  vermiformes  of  the 

cerebellum 

20 

phatics  of  the  under  part 

Appendix  vermiformis  of  the 

of  the, 

OO 

tr 

caecum 

98 

Aqua  labyrinthi, 

55 

the  containing  parts  of  the 

21 1 

AquaduElus  Fall opii ) 

S3 

Abducentes,  or  iixth  pair  of 

18 

nerves. 

232 

Aqueous  humour 

3a 

Absorbent  System, of  the 

153 

Arachnoidea  tunica, 

12 

Acceffory  nerves  to  the  eighth 

Arbor  vitas. 

20 

pair, 

240 

Arch  of  the  aorta, 

174 

Accrvulus  cerebri. 

!9 

Arches  of  the  palate 

62 

Acufticus  nervus, 

Arcus  plantaris  arteriofus, 

221 

Addufbor  oculi, 

37 

-■ volaris  piofunaus, 

1 Q4 

Adeps, 

8 

■ ■ fuperiicialis. 

i?S 

Adipofe  arteries  and  veins, 

207 

Arteries,  of  the. 

1 69 

Alas  vefpertilionis, 

*34 

Articular  nerve  of  the  ihoulder  248 

Albuginea  tunica. 

124 

Arytenoid  cartilages, 

Almonds  of  the  Ears, 

63 

Auditorius  nervus, 

233 

Alveolar  arteries, 

179 

Auricles  of  the  heart, 

76 

Amnios, 

146 

Auris  tranfverfus. 

45 

Amygdalae, 

63 

internes. 

5° 

Anthelix, 

44 

Axillary  artery, 

iqt 

Antitragicus,  ? 

16  6 

Antitragus,  3 

45 

plexus, 

247 

Aorta,  general  ccurfe  of  the 

174 

Azygos  vena, 

199 

Appendages  of  the  ikin 

6 

Ball  of  the  Eye, 

B 

26 

Bladder  of  urine,  blood-vefi'ds 

, coats  of  the. 

ib . 

of  the. 

208 

- 

— , mufcles  of  the. 

36 

of  the, 

158 

veffels  of  the, 

33 

Blood-Vessels  in  general, 

181. 

186 

of  the, 

169 

• ■ , nerves  of  the 

38 

Brachial  artery, 

192 

228 

— plexus  of  nerves, 

247 

Bafilar  Art  ry. 

184 

Brain,  of  the. 

9 

Baiilic  vein, 

196 

, arteries  of  the. 

182 

Bladder  of  urine, 

120 

; veins  of  the, 

m 

VOL.  II.  Z 2 


INDEX. 


page. 

Brain,  nerves  which  arife 

from  the,  - . 22y 

Bronchi,  - s.  gg 

Ccecum  inteftinum,  - ^ 

— abibrbents  of  the  160 

Calamus  fcrjptorius,  _ 2o 

Canals  of  the  cochlea,  - rj 

Capfuls  renales,  - II5 

~ , blood-veifels 

of  the  - . 1 1 7.207 

■,  lymphatics 

163 
94 
255 
176 
ib. 

180 
26 

244 
174 
22-2 
I99 
IOI 

7 

181 
186 

!5 


fage. 

Bronchial  arteries  and  veins,  88. 198 
Buccales  arteris,  _ -179 

Bulb  of  the  urethra,  - ijg 


of  the 
Cardia, 

Cardiac  Nerves, 

Carotid  arteries, 

*  artel7>  external, 

■ — , Internal, 

Caruncula  lacrymalis, 
Cauda  Equina, 

Cava,  general  courfe  of  the, 
— ■ , fuperior, 

, inferior, 

Cavvl, 

Cellular  fubftance,. 

Centralis  retins  arteria,  - 

* ■ vena, 

Centrum  ovale  of  Vieujfens, 


femicirculare  gerainum  16 


Cephalic  vein. 

Cerebellum, 

, arteries  of  the. 

Cerebral  arteries, 

Cerebrum 
Cervical  nerves, 

Cervical  arteries, 

Cheek, 

Chorda  tympani,  - 5 

Chorion, 

Choroid  coat, 

" ■ plexus, 

Chvlopoietic  and  Assist 
Ck y 1. opoietic  Viscera, 
of  the, 


196 

19 

184 

182 

J3 

246 

190 


Cilia, 

Ciliary  arteries, 
■ veins. 


afcf  jvbents  of  the, 
nei  res  of  the, 


29 

24 

20 


Ciliary  circle, 

— glands, 

procefl'es,  w 

Cinerltious  fubftance  of  the  brain  14 
Circulus  iridis  arteriofus,  182 
Circumflexa  fe-  f interna,  ? 

moris  arteria,  \ extetna,  $ 2I+ 

hu-  J anterior,  7 

meris  arteria,  £ pofterior,  j 
-offis  ilii  arteria. 


Circumvolutions  of  the  brain, 
— —of  the  cerebel- 


192 

212 

13 


Circus  arteriofus  o(  Willis, 
Clitoris, 

Coats  of  the  eye, 

Cochlea, 

Cteliac  artery, 

Colic  arteries, 

■ veins. 

Colon, 

— — , abforbents  of  the, 
Columns  valvuls  VieuJJhrii, 

carnes  of  the  heart, 

Commiffurs  eerebri, 
Commiflura  mollis  of  the  optic 
thalami, 

Communicans  faciei,  nervus. 
Cord,  umbilical, 

Cornea, 

Cornua  ammonis, 

Cornua  of  the  ventricles  of  the 


20 

185 

138 

26 
Si 

200 

203 

204 

98 

160 

20 

77 

18 

16 

233 

144 

27 

17 


57 

btain, 

15 

r235 

Cor. .nary  veffels  of  the  heart, 

82 

146 

artery  of  the  lias. 

177 

29 

— ■ ■■  of  the  ftomach 

2 00 

16 

Corpora  albicantia, 

21 

ANT 

— cavernofa  penis, 

128 

■ fimbriata,  or  T tenia 

91 

Hippocampi, 

17 

200 

Corp  ra  olivaria, 

22 

rs8 

— ■ pyramidalia, 

ib. 

258 

Col  pus  adipolum, 

8 

2 5 

cailofum. 

!3 

181 

—■  ciliare. 

3° 

187 

■ " 1 - mucofum, 

4 

INDEX, 


page. 


page. 


Corpus  fpongiofum  urethrae,  129 

Cortical  fubftance  of  the  brain,  14. 
Coftal  nerves,  - 257 

Cranium,  nerves  which  pafs 

through  the  bafe  of  the,  227 

Cricoid  cartilage,  - 65 

„ f cerebri,  7 

Cl'ura  \ cere  belli,  3 ' 21 


Cryftalline  len9,  32 

Cutaneous  nerve  of  the  fupe- 
rior  extremicy,  - 24S 

Cutich,  - - - 3 

Cut.s  vera,  5 

Cyftic  arte1-'/,  - - 202 

Cyftis  fellis,  - no 


Dartos, 

123 

Depreflor  oculi. 

37 

Diaphragm,  blood- venels  ot  the  200 

, nerves  ot  the 

*53 

Dorfal  nerves, 

*57 

Drum  of  the  ear, 

47 

Dutt,  cyftic, 

III 

Duff,  hepatic,  - - no 

— — , pancreatic,  - 115 

Dutfus  communis  cholidochus  112 
Duodenum,  97 

Dura  mater,  - g 

, blood--,  eflels  of  the 

11.189 

■ ■ proceffes  of  the,  10 


E 


Ear,  of  the, 

4+ 

Epiglottis,  - - - 63 

— , fmall  bones  of  the, 

49 

Ergot,  or  Hippocampus  minor,  13 

, mufcles  proper  to  the, 

45 

Euftachian  tube,  - 48 

Ear,  external 

44 

Extre  J luperior  - fuperior  7 extre- 

, mufcles  of  the,  vol.  I. 

6o 

mity,  \ inferior  •'  inferior  $ mity. 

Ear,  internal, 

- 47 

Eye,  of  the,  - - 23 

, mufcles  of  the, 

5° 

, coats  of  the,  - 26 

Eighth  pair  of  nerves, 

236 

, humours  of  the,  - 32 

C olivares,  ~j 

, veffels  of  the,  - 38 

Eminentiae-c  mammillares,  5* 

21.22 

, nerves  of  the,  - 38.228 

( pyramidales,  J 

Eye  and  its  appendages,  arte- 

Emulgent  artery  and  vein. 

207 

ries  or  the,  - 180 

Epidermis, 

3 

— — veins  of  the,  186 

Epididymis, 

I2ZL 

mufcles  of  the,  36 

Epigaftric  artery. 

212 

See  alfo  vol.  I.  38 

Face,  lymphatics  of  the. 

167 

.b 

Fifth  pair  of  nerves,  or  par 

, blood-vefiels  of  the. 

185 

trigeminum,  - - 229 

, nerves  of  the, 

235 

Firftpair  of  nerves,  or  olfaftory  227 

Faix,  or  Septum  cerebri, 

IP 

Follicles,  lebaceous  - 7 

minor,  or  feptum  cerbelli,  n 

Fornix,  - - ig 

Fat,  - 

8 

F..iTa,  or  rivna  mavna,  - 133 

Femoral  artery. 

214 

FofTa  navicularis,  - 148 

■ ■ ■■  vein, 

222 

— — Sylv'n,  ■ - 16 

— — , or  crural  nerve 

264 

Fourth  pair  of  nerves,  or  pathetic  228 

Fibula-,-  artery, 

219 

Frsenum  lingua?,  _ 59 

■ vein, 

222 

labiorurn  pudendi,  138 

266 

preputii,  - - 128 

Call-bladder, 

no 

G 

Ganglion  femiiunare  magnum,  239 

Ganglia,  » 

226 

Galtiic  aueries,  - 201 

INDEX 


page. 

Oaftric  veins, 

205 

Generation  and  urine,  Or- 

g an s of,  - 1 16. 1 CQ 

, lymphatics  of  the 

JS7 

— — — , blood -veflels  of  the 

206 

1 • , nerves  of  the. 

261 

Gland,  lacrymal, 

25 

— -,  parotid, 

6l 

— — — - , pineal, 

19 

• ■-,  pituitary, 

18 

, proftate, 

126 

■ , fublingual, 

61 

— — fubmaxillary, 

ib. 

Glands,  arytenoid. 

66 

— — , axillary, 

166 

, bronchial, 

87 

155 

— — — iliac, 

1 58 

— — , inguinal, 

156 

— — , lumbar, 

lb. 

— — , mefenteric, 

160 

— — — , miliary, 

7 

160 

H 

Haemorrhoid alis  f media,  7 

arteria,  \ externa,  y 

214 

■ — —vena, 

204. 

Hairs, 

7 

Head,  lymphaticson  the  outfide 

166 

, blood-vefiels  of  the, 

J75 

Heart,  of  the, 

74 

. , abforbents  of  the. 

164  . 

Hellicis,  j m?Jor’  l 

45 

7 l minor,  \ 

Helix, 

44 

Hemifpheres  of  the  brain, 

!3  ' 

Hepatic  arteries. 

201 

Glands,  renal, 

-■  ■■  falivary, 
febaceous, 

, tracheal, 

Glandulae  ceruminofae, 

concatenatae, 

- Meibomiana •, 
• odoriferae, 


Gians  penis, 

...  clitoridis, 
Glolfo-pharyngeus,  nervus, 
Glottis, 

Gluteal  artery, 

■ nerves 


page. 

- 119 

- 60 
24 

- 87 

- 46 

167 

- 24 
1 30*1 39 

129 


138 

236 

66 

2x3 

265 

140 


Gravid  Uterus,  of  the,  _ 
Great  fympathetic  nerve,  238  ct  seq 
Gula,  or  gullet,  - - 89 

Gums,  57 

Guftatorius,  nervus,  - 232 

Gutturalis,  artcria,  JfuPer.;°r’ 

l inferior,  igo 
Gyri  of  the  cochlea,  - 51 


Hepatic  veins, 

Hippocampus  major. 

Hole  between  the  right  auricle 
and  ventricle  of  the  heart, 
— — between  the  lateral  ven- 
tricles of  the  brain, 
Humeral  Artery, 
vein, 

Hymen, 

Hypogaftric  artery, 

vein, 

lymphatics, 

nerves. 


206 

17 

76 

17 

192 

196 

140 


212 

223 

*59 

261 


I £*? 


Jejunum,  - "79 

, latteals  of  the,  160 

Iliac  arteries  and  veins,  208.212.223 
Ilium,  inteftinum,  - 80 

Impregnation,  changes  produ- 
ced in  the  uterine  lyftem  by,  142 
Incus,  - - 49 

Inferior  cava,  - 223 

Inferior  extremity,  lymphatics 
of  the,  - 156 

, blood-  veffcls  of  the  2 1 1 

. , nerves  of  the  262 

Infra-orbitar  artery,  - 179 


Infundibulum  of  the  brain  18 

— of  the  cochlea,  52 

— — — — of  the  kidneys,  118 
Integuments,  common,  - 3 

Intercoftal  arteries  and  veins,  120 

nervesj  - 237 

Intestines,  - 79 

■— abforbents  of  the  159 

Iris,  - - 27 

Ifthmus  hepatis,  - 108 

■ fau  ium,  * 63 

VituJJinii , - 7® 


INDEX, 


page. 


page. 


Iter  ad  tertium  ventriculum, 
quartum  ■ ■ ■ ■ ■ , 

Kidneys, 

Labia  pudendi. 

Labial  artery, 

Labyrinth  of  the  ear, 
Lacrymal  artery, 
Lacteals, 

Laftiferous  dudts. 

Lamina  fpiralis, 

Larynx, 

Laryngea  fnperior,  artcria, 
Laxator  tympani. 

Leg,— fee  Inferior  extremity. 
Levator  oculj, 

Ligamenta,  J J uteri 

Ligaments  of  the  liver, 
Ligamentum  fufpenforium 
penis, 

Lingual  artery  and  vein,  171 

Malleus, 

Mammae, 

Mammary  arteries  and  veins, 


Maffeteric  arteries, 


C dura 


fee 


Dura  } 


r 


Mater,  < ■ 

’ dPla 
M atrix, 

Maxillary  artery,  external, 
. , — , internal, 


-{! 


fnperior, 
inferior. 
Meatus  auditorius  externus, 

internus. 

Median  vein, 

— nerve, 

Mediaftinum, 

Medulla  oblongata, 


Nails, 


nerves  of  the 


18 

Jugular  vein,  external. 

185 

18 

189 

K 

Il6 

L 

138 

Lips,  - 

57 

177 

Liquor  amnii, 

346 

Si 

73 

1S1 

Liver. 

106 

153 

161 

70 

— — , bloorf-velTels  of  the, 

108 

52 

201 

»4 

2S9 

376 

Lobes  of  the  brain. 

!3 

5° 

of  the  liver. 

107 

— — of  the  lurgs, 

84 

37 

Locus  ni0ei-  crurur-t  cerebri, 

21 

Lumbar  arteries, 

2 1 1 

> *34 

263 

107 

Lungs, 

84 

— , lymphatics  of  the, 

164 

128 

— — , blood-veflels  of  the  88 

.174 

;.i86 

— ...  nerves  of  the, 

254 

232 

M 

40 

Medulla  fpinalis, 

24I 

68 

Medullary  fubftance  of  the 

brain, 

14 

!.i99 

Membrana  cellularis. 

7 

ib. 

— pupillaris,  - 27*147 

179 

Membrana  tympani, 

47 

— lecundarii 

1 S4 

Meningeal  artery, 

178 

133 

Mel’enteric  blood-veflbls, 

202 

177 

nerves, 

260 

173 

Mefentery, 

IOO 

186 

Mefocolon, 

ib. 

231 

Meforedlum, 

ib. 

232 

Metatarf;  1 artery, 

219 

46 

Modiolus, 

52 

51 

Motores  oculorum,  or  third 

196 

pair  of  nerves, 

228 

2CO 

Mouth,  of  the. 

57 

72 

Mufculo-cutaneous  nerve  of 

21 

the  fuperior  extremity. 

2 49 

N 

6 

Nerves,  of  the, 

224 

>•189 

, cerebral, 

227 

245 

245 

INDEX', 


page. 


Ninth  pair  of  nerves, 

238 

Nipple,  or  papilla, 

69 

Noni  defeendens  nervus, 

238 

O 

Obliquus  oculi,  ^ 

37 

Obturator  artery, 

213 

nerve, 

264 

Occipital  artery, 

177 

— vein, 

186 

OEfophageal  arteries  and  veins 

198 

OEfophagus, 

OEthmoidalis  J anterior,  7 

89 

102 

arteria,  5 pofterior,  \ 

Olfadlory,  or  fir  ft  pair  of  nerves  227 

Omentum,  or  cawi. 

IOI 

Opthalmic  artery, 

180 

P 

Palate, 

5^ 

- — , arches  of  the, 

62 

Palat'ma  inferior  arteria, 

177 

Palmsru  profunda  arteria, 
Palmar  arch,  deep, 

294 

a. 

195 

•= — - — - nerve, 

252 

Palpcbrs, 

Pancreas, 

Panniculus  carnofus, 
Pap  of  the  throat, 

24  - 

314 

9 
5 8 

Papilla, 

69 

Papillae  of  the  tongue, 

Par  trigeminum,  or  fifth  pair 

£9 

of  nerves, 

229 

Parotid  | ? 

l g'and,  J 

6 1 

Pars  vaga  of  the  eighth  pair 

of  nerves,  - 236.254.259 

Pathetic,  or  fourth  pair  of  nerves  228 

Pedes  hippocampi, 
Peduncuii  of  the  brain  and 

17 

cerebellum, 

21 

Pelvis,  lymphatics  of  the 

158 

— — , blood-vefiels  of  the 

211 

, nerves  of  the 

262 

Penis, 

128 

— , lymphatics  of  the 

*57 

, blood-vefl'els  of  the 

208 

— •,  nerves  of  the 

261 

Pericardium, 

73 

page. 


Nose,  of  the,  - 40 

Nymphs,  - - 139 

Opthalmic  vein,  - 188 

nerve,  - 229 


Optic,  or  2d  pair  of  nerves  31.228 
Orbiculare,  os,  - 49 

Organs  of  the  fen  fes,  3 

—————of  urine  and  generation 


in  the  male,  116 

in  the  female,  - 132 

lymphatics  of  the  157 
blood-vcfi'els  of  the,  206 
nerves  of  the,  - 261 

Os  tincse,  - - 134 

Ova  1 

Ovaria,  J ” *35 


Perineum, 

Peritoneum, 

Peroneal  artery. 

Pharyngeal  artery, 

Pharynx, 

Phrenic  nerve, 

Pia  mater, 

Pinguedo, 

Placenta, 

Plantar  artery  and  arch, 
Pleura, 

Pomum  Adami, 

- 

Popliteal  artery, 

— — - vein, 

Ports,  vena, 

Portio  SmoUis^oftheythj 
Lams,  i pair,  1 
Prepuce  of  the  penis, 

— of  the  clitoris, 

Profunda  femoris,  arteria, 
vena, 


-humeri  arteria, 
-penis  arteria. 


Pfalterium  fornicis, 
Pterygoideae  arteriae, 
Pudendum, 

Pudic  artery, 


138 

92 

219 

266 

rv 

63 
253 

12 

8 

145 

220 

71 

64 


227 

223 

205 

233 

128 

139 

215 

22a 

19a 

210 

17 

179 

200 

aio 


INDEX. 


Pudic  nerves, 

pulmonary  artery  and  veins, 

Radial  artery, 

■■  nerve, 

Ranina  arreria, 

. vena, 

Receptaculum  chyli, 
Reftum, 

— — , lymphatics  of  the, 


page. 

261  Pupil  of  the  eye, 

174  Pylorus, 

R 

193  Recurrent  nerve  of  the  eighth 

pair, 

radial  artery, 

ulnar  artery, 

Renal  artery  and  vein, 


194 

176 

1 '36 


90 

9S 

*59 


nerves, 

Retina, 


pagt. 

27 

. 95 


2 54 

193 

194 
207 
261 

3* 


Sacral  artery, 

■-  lateral  arteries, 

nerves. 

Salivary  glands, 

Saphaer.2,  vena, 

r ’ ’ 1 minor, 

Saphaenus,  nervus. 


211  Soermatic  artery  and  vein,  125.207 


213 

265 

60- 

221 

264 


srd, 

nerves, 

Sphin&er  reficse, 

Spinal  Marrow,  of  the, 
— — — nerves,  origin  of  the, 
Spinalis  dorii,  fee  vol.  I. 


125 
261 
121 
241 
ib . 
86 


Scala  $ tyraPani’  X 

Spiral  nerve, 

249 

bcata’  l vefcibuli,  J 

Sz 

Splanchnicus  nervus,  257 

.259 

Scaoular  arteries, 

192 

Spleen, 

1 12 

■ nerve, 

248 

, lymphatics  of  the, 

162 

Sciatic  artery. 

214 

Splenic  artery. 

202 

Sciatic  nerve, 

266 

Splenicvein, 

204 

Sclerotic  coat, 

28 

— — ■■  nerves, 

260 

Scrotum, 

122 

Spongiofum,  corpus,  urethras. 

I29 

Sebaceous  dudts, 

7 

Stapedius, 

5° 

Second  pair  of  nerves,  or  optic, 

201 

Stapes, 

49 

Secundines, 

144 

Stomach, 

02 

Semicircular  canals  of  the  coch- 

— — , abforbents  of  the  96.161 

lea,  - 52 

Semilunar  ganglion,  - 259 

Seminal  veflels,  - - 126 

Senses,  Organs  of  the,  3 
Septum  cerebri,  or  falx,  - 10 

Septum  cerebelli,  - 11 

" lucidum,  - 16 

■■  penis,  - 129 

— - ■ fcroti,  - 122 

Seventh  pair  of  nerves,  - 233 

Sinufes  of  the  dura  mater,  12.188 


Sixth  pair  of  nerves, 
Skarf-lkin, 

Skin, 


262 


, blood-veflels  of  the  93.200 

— ■ ■,  nerves  of  the  96.259 

Sublingual  artery,  - 176 

Submental  artery,  - 177 

Suboccipital  nerves,  - 245 

Superbus,  - 37 

Supercilia,  - 23 

Superior  cava,  - 199 

Superior  Extremity, 

• , lymphatics  of  the, 

— — — — , blood-veflels  of  the, 
nerves  of  the. 


Supra-orbitar  artery, 
Sympathetic  nerve, 


i65 
190 

s45 
182 
238  etfej. 


Taenia  hippocampi,  - 17 

• femicircularis  of  Haller,  16 
Tarfea  arteria,  - 218 

Tarfus  of  the  eye-lids,  - 24 

Tela  choroidea,  - 17 


Temporal  artery, 


Tenfor  tympani, 
Tentorium  cerebelli, 
Teftes, 


*79 

185 

5° 


INDEX, 


„ page. 

Teftes,  lymphatics  of  the  - 158 

— ■ — , blood-veflels  of  the  125.206 
— nerves  of  the  261 

Thalami  nervorum  opticorum  15 
Third  pair  of  nerves,  or  mo- 

tores  oculorum,  - 228 

Thoracic  du  ft,  - 90.163 

Thorax,  of  the,  - 68 

■ ■ , blood-veflels  within  the  197 

— — , nerves  within  the 
Throat,  of  the, 

' inferior, 


253 

62 


Thyroidea  arteria  ^ 
Tibial  arteries. 


fuperior. 


190 

176 

218 


Tonfils, 

Torcular  Hemphill, 
Tradfus  optici, 

Tragicus, 

Tragus, 

Tricufpid  valve, 
Trochlearis, 

Tuber  annulare, 
Tubercula  quadrigemina, 
Tuberculum,  Lotveri, 
Tubes,  Eujiachian , 

— — — , Fallopian, 

Tunica  albuginea, 

arachnoidea. 


page, 

63 
12.188 
16 
45 
- 44 
77 
37 
z'j 

J9 
76 
48 
* J35 
123 
12 


— veins, 

221 

aranea,  or  vitrea. 

35 

nerve, 

266 

choroides. 

29 

Tomentum  cerebri, 

*3 

, fclerotica. 

28 

Tongue,  of  the, 

59 

■■  vaginalis, 

123 

— - , lymphatics  of  the 

167 

Tympani  laxator. 

5° 

1 , blood-veflels  of  the 

176 

Tympanum, 

47 

, nerves  ot  the. 

232 

U & V 

Vagina, 

136 

Vermiform  appendix  of  the 

Vaginal  artery, 

209 

c cecum, 

104 

Valves  of  the  abforbents, 

i>4 

Vermiform  appendages  of  the 

173 

cerebellum, 

20 

76 

Veflca  urinaria,  120- 

-I32 

Valvulacoli, 

ICA 

A^eficalis  ima  arteria, 

214 

Vafa  brevia,  - 202.20c 

Veficula  fellis, 

I IO 

» efterentia  of  the  teftes, 

126 

Vcftible  of  the  labyrinth, 

51 

5 efterentia,  1 of  the  ab- 

of  the  pudendum, 

139 

£ inferentia,  y lorbents. 

155 

Viscera,  of  the, 

3 

laaea  5Primi’  ?&ene‘ 

Vitreous  humour. 

34 

' £ lecundi,  5 ris. 

160 

Ulnar  arteries, 

194 

Vafavaforum, 

I70 

- nerve, 

25I 

Veins,  of  the, 

I72 

Umbilical  cord, 

144 

Velum  Vieujfenii , 

20 

artery. 

208 

Vena  cava,  general  courfe  of  the 

174 

Volar  arches, 

195 

- ■ — luperior, 

199 

Vorticofe  veins, 

186 

, inferior, 

223 

Ureters,  . - 119 

•J33 

Vena  magna  ipfius  penis, 

210 

Urethra,  - 130.139 

Vena  portae, 

205 

Uterus,  of  the, 

133 

Ventricles  of  the  brain. 

15 

. — appendages  of  the, 

134 

of  the  heart, 

76 

Uvula, 

5* 

43 


Zonula  ciliaris- 


4 


